Thirty days, unless something in the job moves faster than that. In 2026 several things do. The Bureau of Labor Statistics recorded a 5.0% jump in lumber prices in July alone, and NAHB's framing lumber composite then fell 6.6% in the month to August 28, landing at $521.35 per thousand board feet. On an $8,000 framing package that swing is about $530 you keep or eat, decided by nothing but the date at the bottom of the page. So: 30 days when labor and stock material carry the job. Seven to fourteen when a tariff-exposed material carries it. And never longer than your supplier will hold his own price, whatever he told you on the phone.
What is the expiration date actually protecting you from?
Not the customer. It protects you from the gap between the day you priced the work and the day somebody signs, which is the only stretch of time where a price can move while you are the one holding it.
Two clocks run in that gap. Your supplier's price hold is one. How long the customer takes to decide is the other. Your window is the overlap, and if you set it out of habit rather than from the shorter of those two, you are quoting a number you can no longer buy.
None of this is theoretical this year. BLS put final demand construction up 2.2% in July 2026 - one month, not a year. Processed goods for intermediate demand, which covers most of what a supply house sells you, rose 9.9% over the twelve months to July. Increases like that do not arrive evenly across the calendar. They arrive on the day a duty lands.
When should the window be seven days instead of thirty?
When a single material carries the job and that material is exposed to a trade action, a mill announcement, or an index that has been moving. Everything else stays at 30.
| What carries the job | What has moved | Window |
|---|---|---|
| Labor plus stock material - paint, fasteners, standard trim | Framing lumber down 6.6% in the month to Aug 28, up 9.3% year over year | 30 days |
| Framing packages, sheathing, imported plywood | Lumber up 5.0% in July; 50% Section 338 duty on certain Canadian plywood from Aug 22 | 7-14 days |
| Cement and concrete flatwork | Cement named in the July 20 proclamation behind that duty | 7-14 days |
| Panels, wire, metal derivative products | Covered as certain metals and derivative products under the same action | 7-14 days |
| Cabinets, windows, anything with a lead time | Manufacturer price letters and tariff pass-through, both arriving with little warning | Match the supplier's hold date and print it |
That Section 338 duty is the cleanest example a contractor is going to get. Proclaimed July 20, 2026. Set to take effect thirty days later, slipped three days, and landed at 12:01 a.m. Eastern on August 22 - and it applies even to goods that qualify under USMCA. So a thirty-day estimate written the week of the announcement expired the same week the duty hit. Signed on day 29, you would have been buying at the new number and billing at the old one.
The softwood duty moved the other way over the same summer. NAHB reported Commerce cutting the combined antidumping and countervailing rate on Canadian softwood lumber from 35.16% to 24.83%, with the antidumping piece alone dropping from 20.56% to 10.66%. Good news, and it makes the same point. A ten-point swing on the largest material line in a framing job is not something you want to have promised across.
Can a customer accept an estimate after it has expired?
If you dated it, no. Their power to accept ends on the date you named. Restatement (Second) of Contracts section 41 sets the rule: acceptance ends at the time the offer specifies, and where the offer specifies none, after a reasonable time.
The trouble is that second half. Reasonable time is a question of fact, which is a polite way of saying it is an argument. You can also pull an estimate before it is accepted - an offeror keeps the right to revoke unless he has expressly agreed not to. Legally you are covered either way.
That is not why you put the date on.
You put it on because it makes the re-quote conversation ordinary instead of a betrayal. A customer sitting on your number for six weeks and then calling to book is not trying to take you. He thinks the price is the price. Every minute you spend explaining why it went up teaches him your numbers are soft, and that costs more than the money did.
Notice which side of this the law actually helps. UCC section 2-205 makes a merchant's signed written offer to sell goods irrevocable for the period stated, up to three months. Your remodel agreement is services, so that rule is not yours. It belongs to your supply house. When the counter hands you a written quote with a date they will honor through, that is the firm offer, and it is the only one of the two documents with a price genuinely nailed down.
Which is the reason to ask for it. Counter quotes print "prices subject to change without notice" by default, and most contractors never push past it. Get the quote number and the honor-through date in writing before you drive home and build the estimate around it. On a screened porch in Cape Coral, the gap between a verbal "yeah, that'll hold" and a printed date is about two weeks of exposure on the biggest line in the job.
What should the expiration line say?
Name a date, then say what happens after it. Most estimates manage the first half and stop.
"Prices subject to change without notice" is the line to cut. It does not say what changes, when, or by how much. So it does no work in the conversation where you need it, and it reads to the customer as a warning rather than a term.
Closer to this:
This estimate is valid through October 1, 2026. Material prices are held by our supplier through September 24, 2026. If the work is authorized after that date, framing lumber and sheathing will be re-priced at cost and you will have the revised figure in writing before any material is ordered.
The date is doing one job there. The named material is doing another, and what-happens-next is doing the third.
If the customer will sign something longer, copy the mechanism ConsensusDocs put in its 200.1 amendment: list the specific materials the clause covers, set a baseline price for each, then adjust against an objective market index instead of your say-so. Naming the index is the part that survives the conversation. It stops the adjustment being something you decided and makes it something you both look up.
What this misses
Trade actions move faster than articles. The August 22 duty slipped three days from its first effective date, and the softwood cut had been expected in July before it landed later. Every figure here was current on September 1, 2026. Check the HTS lines covering the materials you actually buy before you lean on any of it.
A published index is not your price. Madison's composite is a market average. What your yard charges you carries freight, their margin, and whatever they paid for the stock already sitting in the racks - so it lags the index by weeks, and it can sit still while the index moves.
Short windows cost goodwill on small work. On a $900 drywall patch a seven-day expiry reads as pressure and buys you almost nothing, because the material is four sheets and a bucket of mud. Use 30 there and carry the risk. This is a tool for jobs where one material line is big enough to hurt.
Escalation language only works signed. Plenty of residential customers will not accept it, and pushing it on a $6,000 job can lose you the job. Shorten the window on those instead. Same protection, no paperwork.
The window belongs on the page beside the exclusions and the payment schedule, which is what a complete estimate carries. It also means different things depending on whether the document you handed over was an estimate or a quote, because a quote with a date on it is the one that ties you to the number. If lumber is the line that moves on your jobs, the material split in what to charge to build a deck is where to start. BidWalk builds the estimate off your own rates while you are still standing in the house, which shortens the other clock - the one between the walkthrough and the signature, where most of this exposure actually sits.
