Also, if you want to save time AND if you have a super complicated workout that involves 30 different weights on the bar you are also doing it wrong. for each exercise you should have 2 weights: warmup and the weight you are working on. work with a weight that allows you to do 5 sets of 5 reps (+1 warmpup set). Do: bench press, overhead press, squats, barbell rows. that is all. you will get the workout done in 30 minutes. Compound movements with a barbell are all you need (before you gang up on me, remember we are optimizing for time and the best return for the effort).