Try anything just once???

I believe that before you can say 'no' to something you have to try it at least once...Of course I have my limits as to what I WONT TRY (if you catch my drift)...But as for drugs,drinking,smoking...heck skydiving!...Basicly before you can tell someone there stupid for doing this,or doing that you have to have experince....So what do you think??...Would you be willing to try everything once...What are your limits??