When I built my new shop a couple years ago, I new I had to have plumbing no matter what the cost. My first shop I built, I skimped and didn't have any running water. While it was a great little shop, it was a total pain to have to run into the house every time I needed to hit the head or rinse my airbrush. I used everything I learned from my old shop and put it into the new one. The first time I used the toilet in my new shop, the $2100.00 I spent on plumbing and fixtures was all but forgotten. Likewise, in my old shop, the first time I needed to hit the head and couldn't...I was kicking myself all the way to the house!
My new shop has a toilet and large sink with hot and cold water. WiFi, Cable and a Mini-Split heating and cooling unit. And don't forget the beer fridge! All the comforts of home.
Of course you can always add all that later. But it was easier to do it all in one shebang.