I would estimate spending about 6 hours on the initial calibration and several more doing minor tweaks it since then. I started out with ABS and have had pretty good results so far. I can't complain at all, my very first print was a usable part.

I believe being extremely picky with your initial setup and alignment will save you a lot of headache in the end. Calling something "close enough" will only cause frustrations later. My best advice to someone new to the hobby would be: take your time, double\triple check everything. Patience is key!