I'll weigh in on this one since I just added a sub panel to my shop. After much time at the computer planning and pricing, I went with a 100 amp panel simply because it offered more spaces for breakers. I also got a deal on the panel with several breakers in a package deal and it ended up only being around
$20 dollars more over the 50 amp.
I also have a space heater in my shop that requires 30 amp 220 and if I'm running my TS and DC at the same time it pulls quit a load.
Personally, if you are going to add more tools later, why scrimp to save a few bucks.
My Dad always told me "Can't Never Could".
SWE