A pay app is a request, not a deposit. Between the work and the cash there is a review, a certification and a payment cycle, so a job can be profitable on paper and still need cash for months. Most jobs follow an S-curve: slow at mobilization, fast through the middle, slow again at closeout.
Three terms shape the gap. The owner payment lag is how long after billing the money arrives. Retainage holds back part of every bill until the end, so the last slice of cash comes long after the work. And pay-when-paid clauses let a GC pay its subs only after the owner pays, which shifts some of the timing risk down the chain (a stricter pay-if-paid clause shifts the risk of non-payment itself; enforceability varies by state).
The number to watch is peak cash need: the deepest point the job's cumulative cash goes negative. That is the money your company has to fund from working capital or a line of credit. Two jobs with the same margin can have very different peaks depending on payment terms, retainage and how much work is subcontracted.
Knowing your peak before you sign lets you negotiate terms, plan your line of credit and decide how much work you can take on at once.