For powerlifting and related high-resistance exercises, we tend to alternate between higher (10) rep days and lower (5-6) rep days. Obviously, the number of reps reflects the max weights that we can do at those reps. 10 reps means you can't do 11 with good form.
Of course, over time you keep upping the weights.
Our format is to do a light warm-up with the specific exercise, then only four-five working sets. And that's it for my weekly deadlifts, for example. A younger person could do more each week (like twice), but there is a time consideration too.
Our typical weight exercises are below the fold -
Monday:
Bench press
Barbell Squat
Inclined dumbell press
Dumbell Rows
Pull-downs
Thursday:
Deadlift
Overhead Press
Lateral pulls
Seated pulls (weighted rows)
Dumbell Lunges
Tricep push-downs
Those are not the only weighted exercises I do in a normal week, but those are all the relatively- heavy ones.