I know many will dissagree, but I like to run all set to failure/near failure, and I use the approprate amount of wieght for that........ BUT...... I'm always out of breath after each set....... so, I like to take a long enough break that I get my breath fully back, which is sometimes as much as 5 minutes...... I'm not training for endurance or calorie burn.... I just want to lift as much weight as possible (with proper form)..... so I take a long time on squats and deads.