Scope creep, the nemesis of any and every contractor.
The worst one, contractor budgets for i.e. 3 hours, then it takes entire day with the unpaid for added jobbies.
One sees the job, quotes, and then it goes sideways.
Tough question that.
Recently I learned this from a old-toppie contractor.
Actually two sperate contractors.
Both quoted for jobs, different ones, paid for that. The scope creep occured.
So I asked them: What would this cost extra, and that?
Both times they looked me straight in the eye, went like this:
You already paid for the whole day. The guys may at times sit and wait. May even finished in half a day. Refund owed if that happens
So seeing as you already paid for the day, if we can do it today, go and get the material, will see if there is time.
3rd Contractor (other job), also quoted a whole day for the job. With each little scope creep, he charge extra on the invoice. I fully accepted that. It is how it works.
Then they where finished late morning, not late afternoon as I paid for … won’t be seeing him again.
So it all depends on the contractors business model.
Also had contractors, they note the new scope creep down, detailed. But don’t touch it. They focus only on what they quoted for. Disciplined.
Next day, a quote for the additional scope.
Respect.