I wanted to get some feedback from everyone. I currently do a nightly workout routine at home that consists of 5 sets of 20 reps of bicep curls using a 15 lb dumbell for each arm. I also do the same reps in over the head tricep curls with those same weights. I was wondering how can I tell if I am ready to go to a heavier dumbell such as a 20 or 25 lbs bell?