As Homer would say "Dooohhhhh"Or you could do like I did one time, I was in a rush trying to get a order submitted and instead of ordering 14 Large White Gildan tshirts, I ordered 144 Large Gildan shirts. Ooopppps, I was a little surprised when they came in the next day.
When the UPS guy came in with a dolly I was like damn that's a lot of boxes for 150 shirts, little to my surprise it was actually 290 shirts. I was so mad at myself. Needless to say I still have a lot of large white tshirts laying around here.As Homer would say "Dooohhhhh"
Yes experience will help you the most. When I first started I definitely ordered more extra shirts than I do now.It's fun when you get an order for 5 colors in 5 sizes! I just did this and I didn't really need to order any extra.
The key is the spot gun remover! ..and experience.... I have alot of test pellons to make sure job is properly setup before ink hits the shirts, old tees work well too. Also, watch your fingers every time you touch the ink, spatula, container, squeegee...