My woolies one gave up the ghost after 10-12 years, just a few days ago. As the saying goes, it doesn't owe me anything.
Not sure what the problem was yet, it wasn't working hard (sanding drum taking glalvanising of a small piece of sheet steel).
The problem since ages ago has been the spindle lock barely working, which makes tightening the post-fitted dremel chuck difficult. I fitted a short dummy collet to operate the chuck. The dremel chuck is not what I would call 'accurate'.
I have lots of collets from one of those '200 piece' sets, but sadly they don't fit the woollies wonder, so I have many accesories I can't use 
In its time it has done many jobs, now I have to think about a replacement, I was thinking of biting eh bullet and going for Dremel, but if an Aldi one comes up I may take the chance. If either can manage at least a decade of abuse, I won't complain.
Neil