How many take there trimmer heads (straight shaft)(quick links attachments) apart clean and regrease? I do mine about every three years. Don't take but about 30 mins. I find that the grease is about gone and dirty after about 3 years of heavy use. I have several over 10 years old and they still look like new inside. MTD/Ryobi are actually very well made, have 4 bearings and a cast al. housing. I also clean and regrease the shafts also.
If you haven't every done yours it maybe time to do it, if you want it to last....? Rc