I don't need a rest since I only do one set
But if I did I would rest however long it took to perform optimally. Not a big believer in making things more intense through minimal rest and making it more of an endurance workout. Mechanical tension, structural damage more important than mere "sweat."
But what's most important is doing something you enjoy or else you won't do it.
I always go as heavy as I can for the reps I`m shooting for.........I never go below 6 reps anymore, and only go that low occaisionally.......gett ing old sux !!
I think some like Dante Trudel aka Doggcrapp recommends like 15 reps for those a bit older, maybe over 40 year olds. For safety. I do think you can effectively build muscle with higher reps. Some say the important part is getting the high mechanical tension by going to failure. I don't think the failure point is
the trigger per se as Mentzer thought but working in that approximate area is important.