I've started going to the gym to work on fitness, and for weights I find sets of 16 reps far better than 15 reps (the generic starting number for the sort of work I'm doing)
For really light loads I just count to 16.
If slightly heavier I count to 8 twice. 8 lifts isn't so unreasonable, right?
When pushing heavier amounts I recurse again and do 2 sets of 2 sets 4. Listing something heavy four times is no big deal.
If I feel like I should break into 2 sets of 2 set of 2 sets or 2 I know I'm using more load than I should be for 16 reps.
Physicaly these are all identical to a set of 16, but mentally very different.