Not a lot to learn. The piston seals are what wear most commonly in my experience. They are easy to rebuild for anyone slightly mechanically inclined. Full rebuild kits are pricey.
I no longer use dosatrons in new installations. The etatron fixed 1:128 or peristaltic pumps are cheap and for me it’s just easier to mix to 1:128.if you screw up and send a precipitating mix through a dosatron it chews it up pretty fast. That doesn’t happen with peristaltic style pumps. Also, there is no pressure drop with the peristaltic pump like a dosatron.