I know as an example that if you are forming 219 Zipper brass from 25-35 Winchester brass, you can simply use the FL Zipper die and form the new case in one stroke.
If you look at Redding's case forming info, they often use more than 1 case forming die to get the job done. Obviously the more dies you need the more profit they make.
An extreme example of multiple steps is forming 22 Remington Jet from 357 Magnum parent cases. According to Redding, this is what you need:
22 Remington Jet Form #1
22 Remington Jet Form #2
22 Remington Jet Form & Trim Die
22 Remington Jet Full Length Sizing Die
Redding assumes you will always use a FL sizing die as the last step in any case forming process, even though they do not print that in their catalog. I emailed them and they replied with that extra bit of info for uniformed folks like me.
It would seem to me that if I was going to do two, three or four steps, it would make sense to use a four hole turret press, rather than using a single stage or progressive press. Is this thinking right? Assuming I have no budget restrictions.
I know Stimpy forms his using just the 22 Remington Jet FL Die, making a number of less than full length strokes, and turns the case part way thru the process, and it works just fine for him.