Most budget overruns aren't really surprises — they're the lines that were never in the original number. Learning to read an estimate is the single best way to avoid them.
The three big buckets
Nearly every project breaks down into labor, materials, and fees. Labor is usually the largest and the hardest to compare across bids. Materials swing with the finishes you choose. Fees — permits, disposal, equipment rental — are small individually but easy to overlook entirely.
Always budget a contingency
Set aside 10 to 20 percent for the things no one can see until work starts: hidden water damage, outdated wiring, a code upgrade triggered by the permit. If you don't end up needing it, wonderful. If you do, it's the difference between a hiccup and a stalled project.
Read the estimate closely
Prefer an itemized estimate over a single lump sum, and ask what's specifically included and excluded. Watch for 'allowances' — placeholder amounts for things like tile or fixtures that you'll reconcile to real prices later, and a common source of overruns.
A vague estimate isn't a low price — it's a deferred bill.