I wear one piece at all times. It prevents me from saying its too hot today i'll just wear the jacket. Thats the day you will need a full suit. I rode one time in the last 30 years without it, on my way to pick up my suit after getting zipper replaced and had to lane split at a stop light because lady behind me was not stopping, she hit the car I was stopped behind. And if you want to do a trackday with pro6, i'm pretty sure this year its one piece only.