Definitely wear them. You are risking long term hearing damage if you don't. On a 250 it is painful to not wear them. I even wear them in the pits during an endurance race. Especially a 24hr.
Earplugs are a must for me. With plugs in, as soon as the helmet goes on I feel like I'm in my own little world.
I tried using earplugs once...it is really hard to get them out while on the track :-( I did not like them at all, it was actually hard to concentrate because it was so quiet. Also, you cannot hear your competitors brake rotors humming with earplugs in...there is something to be said about knowing exactly when the person you are trying to outbrake even touches his/her brakes. I have used that to my advantage.
I tried some earplugs this past weekend and hated them. I guess I should try them a couple more times, but I HATE having things in my ear. It makes me concentrate on my ear rather than on the bike, which could be really bad. Eric
If you don't like the ear plugs try a different type. There are wax, foam, rubber, and cottony ones. Plus there are custom formed ones. Find one you like you will be happier when you can hear when you start running the crusty class