What are you guys doing to them? I have 2 16 horse and they dont leak at all. and both are probably 1998 motors, just change the oil and fliters and have not had any problem, Did have one that did leak but that was comming from the fill tube due to it needed a valve job, did that and fixed that problem and no more oil leak on it either, have 2 other motors one 18 horse and one 20 plus horse power, cant remember what power, but they have never leaked either. 3 of those motors are on pressure washer units and one on a old sweeper that i dont use anymore. Briggs motors have done us very well. My guess would be if your valve covers are cracked and you have to change gaskets that much, you must be over torqueing them, I havent had to change my covers or gaskets, even after valve adjustments we leave the same ones on them. All our motors have so many hours on them i couldnt even guess at how many.