My check list for chargeable estimates;
If I put on the tool pouch, charge
If I have to go back to office and make calls and pricing, charge.
If the stop is quick only within 1 hour than its free.
Ballpark on the phone has eliminated alot of wasted time.
I used to run around every sat. with no reward, people love to here "free estimate"
but if they ask me several times if this is free....then I don't take job.