Troy: its best to measure that piston since bikes have been know to blow up with an older piston that shows good comp. however, you didnt do the top end that long ago so i would say youve got ages yet. in hindsight on my yz, i was changing pistons way too often when i could have got away with just new rings to freshen things up. the wiseco you have last well also.
that said, you should see the piston from my 144- it looks worse after 5 rides than the yz did after 5 months.
btw- well done for getting to those races, i am ashamed i still havent been out there yet....but it will happen soon!
cheers
Bruce