Your Slow-Pay Customers Are Borrowing From You — Interest Free

In October 2008 I had $87,000 sitting in accounts receivable and about eighteen days of operating cash in the bank. Six trucks. Twelve guys. Payroll every Friday. The builders who owed me that money weren't bad people. They were just slow. And I was polite. Those two facts together nearly killed my shop.

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The Moment the Invoice Hits 31 Days, You're a Bank

Stop calling it a relationship problem. It isn't.

The moment your net-30 invoice rolls to day 31, your customer has your money sitting in their operating account, working for them, while you're watching your own account drain toward zero. You didn't agree to that arrangement. Nobody asked. But there it is — you're the lender and you didn't sign up for it.

I've put it that way with shop owners and they look at me like I said something in another language. Then they do the math and they don't like what they find.

The math I keep coming back to is the 90-day question: how long could you pay your guys and your bills with zero new revenue? If the answer isn't 90 days, you don't have a business — you have a hostage situation where every Friday is a negotiation. Now look at your AR. Every dollar sitting past 30 days is direct subtraction from that runway. Cash you can't throw at a material order, can't use to cover payroll, can't do anything with.

The customers carrying you past 30 days are shortening your runway in real time. And paying nothing for the privilege.

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You Priced the Job. You Didn't Price the Wait.

I've written about flat-rate pricing books before. My position hasn't changed: training wheels. Useful for a year when you don't know your own numbers. After that, if you're still running someone else's book rate, you don't own a business — you own a franchise of someone else's spreadsheet.

Same logic applies to payment terms. You built your price off materials, labor, truck time, overhead. Did you price in the wait? A 60-day invoice on a $12,000 job means that $12,000 is gone from your account for twice as long as you planned.

Most shops don't account for it. I didn't, for years. I priced the job and hoped the check showed up close to when the invoice said it should. Hope isn't a job cost.

Think about it like materials you have to buy up front for a job that won't close for sixty days. You'd build that into the number. But with receivables, we treat the wait as just part of doing business instead of what it actually is — a real cost of doing the work.

If you can't price the financing risk of net-60 into a job from the start, you're running a favor, not a business.

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The Polite Ones Are the Ones Who Fold

The 2008 crash didn't kill bad shops. That's the part nobody tells you.

Bad shops were surviving. They'd been running on cheap credit and busy builders for years. When things went sideways, some folded. Some didn't — because they'd been running tight all along, cash-heavy service work, no real receivables exposure.

The ones that died quietly in 2009 and 2010 were undercapitalized shops. Owner was nice, customer relationships were real, collections were soft because nobody wanted to make things uncomfortable. At Smith Mechanical, I watched my receivables stretch from 45 to 110 days between October and December of 2008. Not because my builders were crooks. Because they were floating themselves on my money. And I let them.

Every polite "just checking in on that invoice" call you make tells the customer something. It tells them you're not going to lien. You're not going to pull tools. You're not going to fire them. They're making a rational bet every Friday they don't cut a check — that the relationship matters more to you than the money. Every softened call proves them right.

Patient isn't the same as professional. Patient just means you're funding them for free, longer.

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What Whitman Builders Taught Me About "Next Friday"

Whitman Builders was out of Marlborough. Good work, decent projects, residential subdivision stuff. By late 2008 they owed me $61,000 across four jobs. Every Friday I'd call. Always pleasant on their end. Phase Two closing is two weeks away, we'll have everything caught up by then. Two weeks later, Phase Two was still two weeks away.

I kept dispatching crews. Whitman was forty percent of my volume. Pulling out meant laying off guys I'd personally hired. I told myself I was managing the relationship carefully. I wasn't. I was funding their operation because I was afraid of what stopping would cost me.

When it collapsed, I got 38 cents on the dollar through the bankruptcy. On $61,000, that's about $23,000 recovered. The rest — roughly $38,000 — was gone. Money I'd already paid out in wages, materials, fuel.

In 2011 I was in a similar spot with a different builder. About $34,000 across three jobs, all north of 75 days, same "next Friday" cadence. This time I sent a certified letter. Every invoice, every date, every amount. Seven business days to respond. Then I pulled tools and filed the lien on the open jobs.

He called furious. Said I was killing the relationship.

What I said back was that I'd been owed that money for three months and the relationship hadn't done much for me lately. That was closer to true than anything either of us had said in all those Fridays.

I didn't get every dollar back. But I got enough, and I got out before it got worse. The difference between 2008 and 2011 was simple: in 2011, I stopped believing "next Friday" before it cost me everything.

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Terms Aren't a Courtesy. They're a Contract.

Here's where most shops are broken before the first invoice goes out: the terms live on the invoice, not the contract.

By the time you're handing someone an invoice, the work is done. You're standing in their driveway or emailing a PDF and hoping they read the bottom line that says "net 30." That's not a contract. That's a suggestion on a document they already got what they wanted from.

Net-30 goes in the contract. Signed before the first truck shows up. Along with a late-fee clause — one-and-a-half percent per month is enough — not because you'll collect it every time, but because the clause signals you're a business with real terms, not a trade that sends invoices and hopes.

For new customers without a track record with you, COD should be the default. Not a confrontation. Just policy. Cover it at the estimate: "We take payment at completion — here's how we handle that." Done before the work starts, not after you're hoping they don't ask for a discount on the way out.

The GC contracts deserve their own warning. Pay-when-paid clauses — where your payment is contingent on the GC getting paid by the owner — are usually buried in the boilerplate. When you sign one, you're no longer owed money in 30 days. You're owed a promise, whenever upstream decides to honor it. Some states limit how far this can reach. Look at it before you sign, not after you're in for $34,000.

Same with retainage held past substantial completion and punch lists used as collection leverage. That's not disorganization. A GC who holds ten percent retainage and drops a punch list on the last day of the job is using your money to manage their own cash position. Know when the retainage release is supposed to happen. Know when your lien clock starts, because it doesn't wait for anyone to get their act together.

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What You Do Monday Morning

Current AR past 30 days:

Pull every open invoice. Sort by age. Anything 31 to 60 days gets a direct call this week — not a soft check-in, a real conversation: "Invoice X for $Y is past due. I need a payment date I can count on." Write it down when they give you one. Hold them to it.

Anything past 60 days doesn't get a call first. It gets a letter — certified mail, return receipt. List every invoice, amount, and date. Give them seven days. Tell them if it's not resolved you'll file a mechanics lien on the open jobs. Then check your state's lien deadline, because lien rights expire on a schedule that does not care how patient you've been.

Ongoing builder relationships:

If a builder account has been slow for more than one billing cycle, make a decision. Not a plan to manage it — a decision. Are you extending them credit or not? If you are, do it with your eyes open. If you aren't, stop dispatching until they're current. There's no middle option that ends well.

Check your active contracts for pay-when-paid language now, before you're surprised.

New customers going forward:

Starting with the next job you sign — terms in the contract, not the invoice. Have the payment conversation at the estimate. Something like: "Before we get started, I cover how we handle payment upfront — we're net-30, and we take payment at completion on smaller jobs. Just want us on the same page." Ninety seconds. Done. The customers who bristle at that are telling you something before you've done a dollar of work for them. Pay attention.

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FAQ

My best customer has always paid slow but always paid. Do I need to push back on six years of loyalty?

Yes. What you're calling loyalty is one-directional. They pay on their schedule because you've never made a different schedule real. Have the conversation, make it procedural: "I'm tightening terms across the board this year, holding net-30 with everyone." Loyal customers who value the relationship will adjust. The ones who don't were never as loyal as the history made them look.

What do I say when I bring up payment terms at the estimate without sounding like I don't trust them?

Say it like policy, not suspicion. "We're net-30, and on first-time jobs we take payment at completion." That's it. Most customers expect this conversation. The ones who act wounded by it are telling you they were already planning to be a problem.

I'm in a small market — what happens to my reputation if I start filing mechanics liens?

If you've been letting invoices go 90 days without consequences, your reputation for being easy to stiff is already out there. You just don't know it. A mechanics lien is a legal remedy that exists specifically for this situation. The contractor who files a lien when he's owed $34,000 is not the story that gets around. The contractor who never collects and closes up quietly — nobody tells that story, because he's already gone.

Are late fees enforceable, and is it worth the friction?

In most states, a disclosed late-fee clause in a signed contract is enforceable. But the fee isn't really the point. The point is what the clause communicates before the job starts — that you're running a business, not sending invoices into the void. Put it in. Keep the rate reasonable. You won't collect it often. That's not why it's there.

My biggest builder account has a pay-when-paid clause. Can I cross it out?

You can cross it out before you sign, or counter with a hard cap — something like "payment due within 45 days of substantial completion regardless of owner payment status." They might say no. They might not, especially if you're the only licensed mechanical sub in the area who shows up when they say they will. Negotiate it before you're on-site. After you're in for $50,000 is too late.

How do I figure out my actual carrying cost on a slow invoice?

Divide your monthly overhead by 30. That's your daily burn. A $15,000 invoice sitting at 60 days instead of 30 means you floated $15,000 for an extra month while still paying that burn out of other cash. Figure out what your slow AR is costing you in real dollars. Write the number down.