The key is speed and quality. The discs are wet or dry. Most of the time I wetsand with the rotary on the early coats. I find the rotary a blessing (and the PC)....by hand this would take forever....I have to say for the sanding go with the rotary...I feel it saves a lot of time.
To do the hood on my Camry I use 2 (sometimes 3) discs.

I got the 50 pack 4 boxes of Rhino (non loading) for 65$ shipped. So 1 box is $16. You don't have to buy 4 boxes (I wanted different grit sizes). You can get 2 boxes or even one (say a 180 and 400 or do just 1 180 box and you do the rest by hand) well you get the idea. I know I got enough paper for quite a few cars now.

On the final coat I'm doing the wetsanding by hand the buff with the Hitachy rotary and Diamond Cut 2.0 on the compound pad, then PB SSR 2.5 or 3 with the yellow or orange Lake county foam pad, SSR1 to remove the light swirls and micro maring. From then either AOI or PB EX and Natty Paste wax.

The discs are wet or dry.

PB = Poor Boy good stuff, non abrasive polishes,swirl removers..