A warm-up has one job: make the first hard set feel like the third. Five minutes does it. Twenty-five minutes is a second workout nobody asked for.
Straight from the car to the heavy set, a proper five minutes, or so much warm-up there's nothing left.
Get warm. Open up what you're about to use. Then practise the first lift on the way up to today's weight.
The step people skip, and the one that matters most. Same lift, lighter, a few reps, working up. None of it should be hard.
Ramp-up sets don't count toward the workout. If one of them feels like work, the jump was too big.
Two minutes on the part that's about to do the work. Not a tour of every joint you own.
Short answers.
Pick one.