you really do need to change it every 50-60 thousand miles the reason i say this i got one that was towed to the shop today with a broken timing belt and its going to cost a fortune to repair this one,the guy was running about 70 miles per hour when it broke so every valve in it is bent,it and its going to be a really expensive repair to make if it breaks,this one probably around 1200 bucks or more or possibly replace the engine,we don't know yet how bad it is,its better to have it changed than have this happen to it,good luck.