The string may be old and brittle. Try a small pack from a store that sells alot of the stuff (more likely to have fresh stock). I think they get brittle after ~1 year.

Probably running the engine too fast which will wear the string down fast against concrete. Feather the throttle so the engine RPM is just fast enough to cut the grass. You also maybe holding the trimmer head too deep. meaning the string is laying against the concrete to much. try lowing the head just enough till the string touch grass. if your using it to cut a trench along the sideway as you edge then you will use much more string. I can go 300 feet of chain link fence before I even need to advange the string. I do this by low rpm and just letting the string come in contact with the fence. the string whips in and out cutting the grass and not wearing the string down.

Yes, I did run it at max, I thought that was the way to do it. I thought these things are supposed to take a beating though.

not the .095 string, just little tougher than .080. put some .155 on there it will bend chain link fence. I done it both ways and to me the best way is not too much rpm and not too close to your work?? Easier on you trimmer and it burns less gas and you use less string. IMO if you are running corn gas don't let it set in the tank too long. Don't run it for a month drain it out before you use the trimmer.

thank you, good advice!