I have a Homelite string trimmer I bought at Home Depot. It uses
0.080 line fed from a bump-feed head. In 20 minutes of trimming
(mostly walking around), I have to feed line out at least 10 times,
usually requiring several bumps each time. When trimming against an
obstacle such my foundation or even a wood fence, the line lasts about
20 seconds or less before it's mostly gone.

I've seen "fixed line heads" for sale that use pre-cut lengths of
heavy line. Before I waste $10 - $15 on one of these, are they any
better? They seem wastefull, since once the line is about halfway
gone (or as short as you can stand it, I guess), you discard the rest
of it.

Thanks for any tips!