I don't wear one 1-1.5+months out from a competition because I am trying to develop as much general, raw strength as possible. When the competition gets closer, I wear the belt on my heaviest sets in hopes to overload the exercise and to get used to the belt again (for the competition). And I only do chain suspended GMs for max effort work because I only care about my deadlift.
For me, wearing the same gear and doing the same thing everytime I do the same exercise is not a smart/effective way to progress my training.
This training cycle, my best chain sus. GM without a belt was around 525x6. Yesterday, with a belt on my last set I hit 625x1 easy. Thats a 20lb PR for me. So, something worked this cycle! haha.