I go through the following towels on a full detail (drying, polish, wax, interior, etc.):
Drying
-great white drying towel
-4 waterless wash towels
-4 utility towels for tires and wheel wells
-2 waterless wash towels for rims
-2 waterless wash towels for truck bed
-1 glass towel for touch-ups
Glass
-2 glass towels for initial cleaning (I use one for the first wipe and one for final, then I use the final wipe towel as my initial wipe post clay bar)
-1 glass towel for clay bar
-1 glass towel to remove glass sealant
Clay
-2-4 single soft towels (it depends on whether I need to do my whole truck or not)
Polish & SVRT
-2 single softs for SVRT touch-ups and smudges
-3 single soft towels (one for each polish, sometimes more if I have some real heavy correcting to do)
-1 double soft towel for detail spray if needed
Seal, Glaze, Wax
-1 double soft for super machine sealant
-1 double soft for brilliant glaze
-2 double softs for Americana paste wax (I do to coats of Americana)
Interior
-2 waterless wash towels for interior cleaner
-1 waterless wash towel for interior conditioner
-2 glass towels
(If I do my seats, carpet, and floor mats, then you can add about 20 cheap autozone mf's to that list)
Keep in mind that I drive a Ram 1500, so I use probably double or triple the amount of towels and product as most people. Since it's my daily driver, I have to spend quite a bit more time on it as well, even though I keep it pretty close to perfect. More importanly for your question though, I have never finished a full exterior detail in one day and I rarely even think about doing the interior at the same time. So, you don't really need every towel I mentioned, you just have to know how you to break up your detail to use what you have most efficiently. I routinely throw the waterless wash towels I use for drying in the dryer, so that I can use them for the interior when I'm just doing a simple wash. Good Luck!