Butylated hydroxytoluene (BHT), also known as dibutylhydroxytoluene, is a lipophilic organic compound, chemically a derivative of phenol, that is useful for its antioxidant properties. European and U.S. regulations allow small amounts to be used as a food additive.
Like others have said, it depends... If you're doing sets of 8-12 reps with moderate weights, rest 60-90 seconds. if you're doing high weight low rep (3-5 reps), then rest 2 minutes And if you're doing real heavy stuff like squats, deadlifts, I'd recommend at least 3 minutes.
Usually you only make a one-rep increase, but you can increase the number by two or more. When you can't do another set, work your way back down by decreasing the reps in the same way you increased them. Most ladder workouts include a rest period between sets, which is usually less than one minute.