Lifetime of saw blades?

[singlepentode69]

I mainly use a chopsaw now and a jigsaw now and again which always went through blades like a dose of salts .Black and decker did a saw which was called an alligator which I used with great success to cut everything and did a grand job of cutting and pruning of the dreaded leylandi hedges until I got a Stijl chainsaw after the saw gave up the ghost.
Robin