Usually low water pressure (ours freaks out if we dare put the kitchen tap on while it's trying to fill) or blocked filters occasionally after a heavy load.
It's just stopped actually cleaning stuff. Which is a bugger, since that's its only job. I might try a service but I wouldn't be surprised if it needs replacing, it's pretty old.
Sadly probably is yeah. If you have solar (or plan to get solar) best to get a modern one you can set to a timer to maximise your power efficiency anyway.