ok guys. i bought my 2007 kx250f new and rode it from spring to summer and fall.it was never raced, but i rode it almost every day. it was never on the rev limiter all but maybe 4-5 times and was not held there but like i said it was rode almost every day for about 2-3 hours each day i could. i rode it about 75% of the whole time i had it. it has about 35-40 hours on it and i do regualr oil changes. i change the oil and oil filter about every 10-15 hours like the maual call for. i run bel-ray thumper semi synthetic racing oil. i also clean the air filter about ever 6-10 hours. but i just need to know how long u guys think i should replace rings in this.