I always loosen the b&c on my saws after operating. I read this in a owners manual. The manual said if you leave the b&c tight it coul mess the bearings or seals up. I have some pretty old saws, I never bought on new though. So I dont know how the owners before me operated/cared for their saws. I have not had a crank bearing or seal go out on any of my saws. I take it that the manual is right it makes sense to me. I just read a thread that stated someone had a 6 month old saw that torched the piston because of a crank seal air leak. This was in the huskey vs. stihl post. Maybe it was the operator not the manufactuer, maybe?