I am almost always moving Jake around in different bits. He gets used to one and then starts to ignore it. I don't have to move up in power, I just have to change the feeling of the bit. So for schooling english I move between three snaffles : Double jointed loose O-ring (french link), a single jointed D-ring, and a slow/large twisted full cheek when he needs a little more. Right now he is a happy camper in his D-ring, we will see how long that lasts, its normally about 3-6 months.
Then for my show coming up I will be in a three ring elevator bit with no chain. Probably on the first hole. He loves sliding gags, and they work wonders when he is used to a snaffle. It has the extra give when I put tension that gives him a some play. It also helps give me lift for turning, and the possibility of a little extra edge if needed during a show. (He has only shown barrels, I'm expecting him to be HOT HOT HOT for the first few classes)
Now for western I typically switch between the tom thumb and the wonderbit. Honestly I don't like how he works in a tom thumb, but when he is taking advantage of the wonderbit I will go to the tom thumb for about a month to freshen him up. Then he will be a dream back in the wonderbit. I don't do snaffle work western because I want to retain my loose rein western work and my contact english work, and want him to respond differently.