With network licenses, you can have less licenses than you have employees with cad.
For me, I use to cad everyday but now I may open a cad application once every other week. So I only check out a license when I need to. The theory is that not every employee who needs cad, will be cadding at the same time. And for 40,000 person company that saves money.
Figure out what how much cad you are using at any one time and get that number of license plus a tiny bit more for contingency.