John , There is a difinite Love Hate relationship with spiral blades .Like some feel about thier saws, kind of my way or the hyw.,Probabaly more has been written here and other forums about apiral blade than any other ,check the older posts .The issue here really is the design of the blade ,basically it is a standard blade that is twisted evenlly locate a point in a at every point on the compass ,making it able to cut in every direction ,always cutting on three sides at once ,regulated by the direction of force applied ,The major difference in the life of the spiral is due to this twisting action of the teeth to create this type of blade the depth of the GULET the part of the blade that removes the cut wood is reduced to almost nothing in comparison to the same size straight blade ,ADD to that the fact that the same blade is cutting MORE wood ,that twisting adds Width to the blade as well as removing the GULLET depth and is now cutting of three sides at once the Blade is subject to more Wear and Heat than any standard blade Thus shorter life (HINT ,I use a candle touched to the moving blade to help the release and extend the cutting process ) Everbodies is correct ,the dulling of teeth has the effects mentioned ,and blade replacement is the only cure .slowing down the speed and pressure ,and for me a candle really help ,NO Matter what saw you use the Blade is the Boss!!! NOT you You are mearly a guidence system .How well you do your job has more to do with the life of the blade than anything else Lube really helps the release of sawdust on any blade ,if you doubt it try it !When You understand why the spiral is different and follow the rules related ,They work great and have a very useful place ,in you arsonal ,they are not for everything ,although with pactice ,they can do a lot more the Many think !JMHO and I use them a lot .