although I did a repo at a local engineering shop , and there was a pallet full of angle grinders ,,,, I grabbed half a dozen of my favorite branded ones ,, long story short all they needed was brushes or leads replaced ,,, the guys working there just threw them in the corner when they stopped working and got another , usually a cheaper brand by the look of it , but it was more cost effective to get another and keep working than to stop and start to fault find ,,,, fly off brushes are a god send some days ,,,