On Tue, 6 Jul 2010 07:22:14 -0700, GHenry wrote:

I have 150 feet of 0.130" "nylon" string which I cut into foot-long lengths
to fit into the Craftsman string trimmer.

Mine only last a few minutes, five or ten at the most

I just measured the string size after I cut the 150 feet 0.130 nylon.

Each cut is an 18 inch length (based on a saved sample of an original 16"
string); and of those 18 inches, only six inches protrudes out each hole
(so 6 inches is always wasted inside the spool).

Of the protruding six inches, about 2 inches are left after five or ten
minutes, so the "wear" is about 4 inches per side per ten minutes.

That's about 24 inches per hour per side.