I have worn through the bottom of a head, but not a button so far. My sister did somehow manage to crack the button on hers but she could tear up an anvil given opportunity.
I usually do about 80% fill on the head...that's what 4 'arm pulls' from the spool gives me. Typically I will wind with the natural curve of the string. You get more aggressive cutting if you wind against, but breakage potential rises.
Ran the T25 for an hour this morning and experience no one-side stickage. So I guess I'm switching all my units over to these. I'll do a few more rounds to make sure.
Just a WAG “but” is it possible you’re winding the trimmer line on the wrong direction based on the heads rotation? I’ve done this a time or two by not paying attention and had the exact same issue that you described.
