How many 4' lights for a 24'X32' Garage?

I ran into the same question when I built my garage. It is 26' X 30'. After a lot of research I came up with a total of 16 fixtures with two 4' bulbs. That may sound like a lot of light but I hate a dim shop. They are basically laid out evenly spaced four wide and four deep. I set them up on four seperate switches for each row. The units I used are from Menards and are cold start fixtures. They were about $20.00 each. They have been trouble free for about five years now. If you go this route install duplex plugins in your ceiling and use three wire plus ground if you want seperate each row with a switch. I like them and if I ever have a problem with one I can just unplug it and hang a new one. Hope this helps