Do you plan to mod your bike? New exhaust pipe that is less restrictive? New air filtration system that is less restrictive?
Uncorking your bike to get to the last 10 hp that the factory wouldn't give you
throws off the vacuum level and makes the factory vac petcock work more unreliably. It will die eventually anyway due to hardening/cracking diaphragm, etc, but playing "get more power" games that alter the vac level that supports it makes it go whacky a lot sooner.
People do sometimes replace the vac petcock system as a pure reliability issue "pre-emptive strike", but note they also are generally the same folks planning on modding their bikes anyway.
The hard fact is, once you know the trouble symptoms of vac petcock failure you are on the lookout for them and when they first occur a Raptor petcock gets ordered.
Look here for symptoms. Don't just skim it -- READ both pages carefully.
http://suzukisavage.com/cgi-bin/YaBB.pl?num=1251932429/1