>>2043937hydro dicks basically never fail unless you crash, I've never used a rolloff but from what I gather they are insanely complex machines. a hydro dick is not terribly complex once you've mentally accepted that they are not "dick brakes but with fluid", but instead a fairly different concept:
https://www.youtube.com/watch?v=mPptmoy0u3sif you don't crash you'll burn through at least half a dozen sets of pads and a couple of rotors before you even need to start thinking about a bleed (I'm talking about normal mineral oil brakes not the DOT shit which is for masochists)
pad replace is easy, just a multitool, a needle nose pliers, a pad spreader, and new pads. and obviously isopropyl and whatever else you need to stay clean