Somewhere in your subcontract there is a sentence that starts a clock. On an NEC4 form the best known one is clause 61.3: notify a compensation event within eight weeks of becoming aware, or lose the right to a change in price or time. Amended forms often shorten it. JCT forms carry their own notice rules, and bespoke amendments add more.
The clause isn’t the problem. The problem is that the clock starts on site, on the day the event happens, and the clause lives in a PDF nobody re-reads mid-job. The ground changes, an instruction lands by text message, the programme slips a week. Each of those can start a window. Nobody writes the date down, because on that day it doesn’t feel like a deadline. It feels like Tuesday.
Eight weeks later it becomes the most expensive date on the job.
The firms that don’t get caught run something simple: a board of live notice windows, per job. Event, date it started, clause that governs it, date the window closes, who owns the notice. Not a claims strategy, just a list of clocks that are already running. When the board exists, the conversation happens in week two: notify or let it go, a decision someone actually makes. When it doesn’t, the decision gets made by the calendar.
Three habits make the board work.
Write the event down the week it happens. The window rarely starts when the paperwork arrives; it starts when the thing occurred or when you became aware of it. A one-line entry beats a perfect one written late.
Read the amended clause, not the standard one. The unamended NEC4 gives eight weeks. The version you signed may not. Schedules of amendments exist precisely to move terms like this, and the amendment is the one that counts.
Keep the dates where the whole team can see them. A window known only to the person who spotted it closes when that person is on leave.
None of this decides whether a notice should be served or what it should say. That stays with your QS, against the contract. Visibility is the point: the dates on one board, counting down in the open, so nothing is lost to a clause nobody re-read.
If you can’t say today how many notice windows are open across your live jobs, the honest answer is that some are, and the calendar knows which.