Have never had any problems.
I run 87 in everything. Running pure gas would cost me around $100 a week.
I agree with Carscw, I run e10 gas in all my equipment and have never had a problem.
As long as you keep gas fresh and put stabilizer in anything sitting for any length of time you won't have a problem, I also have shut off on all my equipment and run carb dry if it will sit more than one week.
I have a featherlight Weedeater I bought in 2001, only run it dry in the winter always starts at 3rd pull just like new, only problem with it was in July I had to put a new primer bulb on it, I have now idea how many hours it has but it's got to be a lot (only use it at home)
BTW this is only the second gas trimmer I have bought, first one was also a Weedeater don't remember what model it was but in 1980 it cost $250 at OTASCO (Oklahoma chain store) it died at end of 2000 and I got this cheap one spring of 2001 ($69 at Lowes) and it has been a great one.