It is important to know if you’re losing money between quoting jobs and getting paid.
If you quote with a 30% gross margin but you don’t see 30% in your P&L, something’s wrong and you should fix it.
You should set up systems so you do it for every job (yes you should)
If you can’t do that yet, do some spot checks.
It’s not hard (just takes work) – compare your quote and the predicted input costs to the actual input costs; if the gross profit is less in real life than in your quote, find out why and go from there.