Before you book
Check a freight quote before you accept it
A freight quotation is not a price. It is a price for a named subset of the work, and the charges that hurt are almost never the ones printed on it — they are the ones it never mentions, and the ones that accrue per day with no ceiling.
This is the cheapest moment in the whole process to fix that. A charge you get in writing before booking costs nothing. The same charge questioned after the invoice arrives costs a negotiation, and often you lose it.