Ive been repairing small engines for some time and have worked on them all and the older models with the cast iron sleeves or even the newer i/c with the sleeves can last forever, Ive had them come into my shop locked up (LOW OR NO OIL)and have been able to free them up and are still running today, The new alum engines wont last long unless they are maintained, the commericial motors I work on can have 1500/2000 hours on them and still have good compression but then again its all in how they are maintained, Ive seen new motors ruined in 2 seasons because of lack of maintaining them