The one tip is to just do actually do the job and get familiar with the brakes, their condition, and how they work.
It is just my opinion, but I think it adds confidence and caution in equal measure when I know how it works beneath me.
The parts are not expensive in the big picture, even if a $7 O-Ring is priced too high.
I have never had a shop do the brakes on a bike (or any vehicle) for me so I do not really know how much I saved.
It probably took me about two hours or a little more. I was not in a rush, and I was halfway watching a soup on the stove at the same time.
The outer rubber ring (Kawasaki call it the dust cover) is the cheap insurance for the long term life of the pistons and calipers. It is not really a dust COVER. It is recessed into the bore a little bit and leaves a gap where the debris (that hard debris that forms from brake dust and road grime) can collect. That was the real reason I stripped them down all the way. I could not inspect the dust cover O-Ring in situ. Given that I had not owned the bike, I wanted to inspect that with my own two eyes and make sure I was not getting grit or moisture into the bores. (Not something I will worry about again for a long time)
The one piece of preventative maintenance (without stripping them) would be to remove the pads and anti-rattle clip from the caliper every year and clean off the grit/debris well with a toothbrush or scotch brite from the area where the pistons poke out of the caliper. It would be a fifteen minute exercise for each wheel once a year. With a little bit of PM, I can not see a reason to ever need to replace calipers.
The saga continues here with the rest of the service work: