Off the top of my head I would think that two of the determining factors would be (a) proper protection of each piece of equipment and (b) load diversification.
If the equipment or NEC requires a certain size OCP, then you must provide that. Beyond that, load diversification would be taken into consideration. protection.
Your disconnect could feed any number of 15 amp receptacles as long as 15 amp meets the protection requirement and no
more equipment is used simultaneously than the protection allows. For example, you could have 10 outlets at various locations for convenience in moving equipment or for 10 individual pieces of equipment.