On the classic, there is no gauge, so after a crew change there's little you can do about assessment...
I personally approach my hand to the brake assembly, WITHOUT touching, just to have a vague idea... but actually, there is no way in which we can make a GO- NOGO decision.
If the previous crew landed below the max quick turnaround weight, then it's safe to takeoff. Period.
Personal assessments are b******* over these grounds, I think.
Re the need to release the brakes after parking: no doubt it's good airmanship to do that ASAP.