I've been using them since I started riding. I occasionally ride for 5 mins or so without them in every now and then so I can hear the engine and to check if there's any strange noises going on. Then I pop a pair back in (always have about 6 pairs dotted in my leathers, on the bike, up my ar$e, wherever).
After having tried countless pairs, I now swear by Soft FX, they have a great db reducing rate. Get them from here:
http://www.earplugs.gb.com/index.html If it's your first time, they do a trial pack of all 21 differnet designs, good way of working out which ones fit your ear'oles the best.
Ade.