Hourly billing sounds fair: you pay for the time the work takes. In practice it moves all the risk onto you. You can't see the meter, you can't tell a ten-hour job from a forty-hour one, and the person writing the invoice knows more than you do about how long it will run. A flat rate flips that: the price is agreed up front for a defined outcome, so the risk of it taking longer sits with the engineer, not with you. Neither is magic — but one of them lets you compare before you buy, and the other doesn't.
Check these first, yourself
Ask for the total, not the rate: 'What will this cost me, all in?' turns an hourly quote into a single number you can compare.
Write the outcome you want in one sentence. A scope that can't be written down in a sentence is the one that runs long.
Ask what happens if it takes longer than expected — with a flat rate the answer is simple: it costs you the same.
Get the price and the out-of-scope list in writing before work starts, so there is never a surprise invoice.
Should you fix it yourself or call a rescue?
Still have questions?
Isn't hourly cheaper for small jobs?
Sometimes — a 20-minute fix is a 20-minute fix. The problem is you can't tell 20 minutes from 20 hours before you start, which is exactly the uncertainty a flat rate removes.
What stops a flat rate from being padded?
The same thing that keeps any price honest: you compare it before you buy. A flat rate is public and fixed up front, so a high one simply loses to a lower one.