At 58 you are definitely not an "old fogey"lets get that out of the way to start with.
A gig lasts as long as it lasts.... the guys will normally eeek out every bit of extra time to give even more at the end. It depends what time they are booked until and that depends on the venue normally.
Pre book a taxi perhaps and save those legs. Oh and dont forget the hot water bottle and paracetamol!
Just kidding
Jo
Not alot of help really