Thanks of sharing your information. I was a bit frustrated but I would expect you also were last month. The spool that I bought new, could have been in a place where it could be moist. I’m not sure what the plastic is but if it’s nylon it can absorb quite some moisture and then the yielding strength will drop? After I had changed the original spool with the spool with previous breaking cheap wire, it went better but could not get my finger on why. Perhaps the hole has been worn out.

Your suggestion of another trimmer head I will look into. The trimmer start to vibrate more so I’ll check the bearing and see if the trimmer is disassembable (if that’s a word)