I ended up chucking my last Ryobi strimmer away because I couldn't get spares for it - even from Ryobi - it's put me off the brand for life even though the equipment was very good. It wasn't a very old model, maybe 3-4 years.
Depends on what you want with Ryobi, spares are few and far between and, if you do manage to track them down they often cost as much or more than the price of a new tool.
I like them but tens to treat them as 'disposable' when broken.