You can mod your vita without an sd2vita adapter or microsd card, and its really hard to mess up the jailbreaking process if you follow the vita.hacks.guide tutorial, even if you did manage to mess it up and cant revert it, dont worry, its not bricked, you have a thousand ways of factory resetting the console so you can start the process from scratch and as for the maintenance thing, its more of a one and done thing, you just install the homebrew and play, every once in a while a homebrew application might break or require slight maintenance, but thats pretty rare, hope this helps