The only reason you would have to replace the Pressure senors is if you change out the wheels. A lot of aftermarket wheels will accept the stock sensors, but some will not and require an aftermarket replacement. No need to worry about it if all you're doing is replacing the tires. I do agree though, that you should have the "batteries" I guess that's what they are. Replaced at the same time. It would suck to have to remove tires just replace a dead battery...