Honorable mention to the coffee grinders' manufacturer Baratza. They publish detailed instructions on how to repair their grinders, make videos showing how it's done, sell replacement parts and recommend service centers.
For me, it was youtube videos of the grinders being used / reassembled / cleaned that made up my mind. I mean, if you're going to spend $200+ on a grinder, it's nice to know ahead of time that you can fiddle with it.