I'm going to shot by my fellow trades here.
I thought everyone here should be aware of the differences here.
Any job over a thousand dollars should be quoted and a written acceptance from the customer before works begin.
This covers everyone's butt.
When I am asked to quote, it's my job to fully understand the task at hand and any unforeseen problems. If I quote to do a job, thats it. Final price unless otherwise stated in the quote.
Some trades will quote low and then hit you up for variations.
Because I need to allow for unforeseen problems, I need to add a buffer into the quote. If the job runs as planned, I'm infront money wise. If it doesn't, I can lose out in a big way.
So quotes can be dangerous to both sides.
Do'n'charge.
This is by far the fairest way to both parties.
Any unforeseen problems can be overcome properly (as opposed to quickly to save the tradie money) and the customer is only being charged for the work done.
Quoted works can be rushed so the tradie makes the most profit.
On Do'n'charge jobs, the tradie can take his time to get extra money.
If your tradie is do'n'charge, watch his phone time. make sure he's not making calls on your time.