How long are your Shindaiwa trimmers lasting before you have to replace them? We have about 15 260s & 261s and it seems like they lose their power by the middle of the 2nd year. I am not going to totally rebuild one, but we remove the spark arrest screen, make sure the carbs are clean, good spark plugs, fuel filters etc. Could it be our gas/oil mixture? We discovered that our 2.5 gallon cans are not 2.5 gallons - they are closer to 2.25 gallons. There is alot of other things that break on them too, but they have worked better than any of the other manufacturers for us. I feel like we should be getting way more time out of these.