The Internet's Biggest Collection of Expensive Mistakes — And How to Avoid Them.
Every costly mistake has been made thousands of times before. We found them, priced them, and built a database so you never have to learn the hard way.
Real Costs
Every entry shows the average dollar amount the mistake costs, sourced from verified real-world reports. No guesses.
$4,800
Average cost — skipping transmission codes
Confidence Scores
Each mistake is rated by how well it's verified. Community votes, expert review, and data sources all factor in. We flag what's uncertain.
How to Avoid It
Every entry ends with a step-by-step checklist — concise, actionable, tested. Most take under 3 minutes to follow.
- 1Pull stored transmission codes
- 2Check VIN against flood databases
- 3Verify lien status with the DMV
Starting where mistakes cost the most
$4,800
avg. mistake cost
Used Cars
Transmission codes, flood damage, hidden liens
$6,200
avg. mistake cost
Home Repairs
Roof decisions, foundation missteps, bad contractors
$3,400
avg. mistake cost
Hiring Contractors
Unlicensed work, missing permits, scope creep
$8,100
avg. mistake cost
Insurance
Coverage gaps, denied claims, workers' comp errors
$5,600
avg. mistake cost
Legal
Bad leases, skipped clauses, wrong attorney type
$11,400
avg. mistake cost
Mortgages
Wrong loan type, missed fees, bad-timing refinance
Every page follows the same simple anatomy
No essays. No fluff. The mistake, what it costs, how sure we are, and exactly how to dodge it.
Buying a used truck
Mistake #1 — Skipping the transmission codes
Buyers close the deal before pulling stored transmission codes, then inherit a rebuild bill weeks later.
$4,800
Average cost
98%
Confidence
3 min
Fix checklist
Source: verified owner reports
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