You've been there. A bid comes together, the numbers feel right, you send it off — and three weeks into the job, something you never priced shows up and eats straight into your margin. It's rarely one big miss. It's almost always one of a few small, repeatable ones.
Here are the three that come up again and again, across trades, across job sizes.
1. Waste factor that doesn't match the job
Most estimators carry a standard waste percentage — 10%, sometimes 15% — and apply it to every job the same way. But waste isn't constant. A simple rectangular room wastes differently than a job full of angles, cutouts, and custom work. When you copy-paste a waste factor instead of adjusting it to the actual complexity of the scope, you're either padding jobs that don't need it (losing bids) or underpricing jobs that do (losing margin). The fix isn't a bigger number across the board — it's a waste factor that flexes with the geometry of the specific job in front of you.
2. Site costs that quietly add up
Temporary facilities, dumpsters, protection materials, cleanup — these get lumped into "general conditions" and then, too often, estimated as a flat number pulled from memory rather than calculated. On a longer job, a recurring monthly cost that seemed small on day one adds up to a real number by the time you're done. These items deserve their own line, calculated against the actual project timeline, not a placeholder.
3. Scope that's assumed but never written down
This is the quiet killer. You know what you meant by the bid. The client may not. If "site cleanup" wasn't spelled out as included or excluded, if a fixture allowance wasn't clearly defined, if a change in material grade wasn't priced as an option — that gap becomes a conversation you don't want to have mid-project. Every assumption that isn't written down is a future disagreement waiting to happen.
The fix isn't complicated
None of these three are complicated to fix. They're just easy to skip when you're moving fast, which is most of the time. The estimators who consistently protect their margin aren't smarter — they've just built a process where these three things get checked every time, not just when there's time to think about it.
If you want a structured way to make sure nothing like this slips through, that's exactly the gap vegaestimating.ai is built to close.