If you need more than 24 ports (or you may in the future) then a 48 port switch will be better. If you don’t need the extra ports than a 24 port switch will be fine.

*****************************************************
it all depends on your requirements. if all cabling has to route to all 48 ports from a single location, then preferably 48 port. but if your nodes are locally scattered in group, then probably you may not be routing all 48 cables from a single centralized palce, it will be better to cascade and place two 24 ports switches at different locations.

============================
One thing to note is that not all power over ethernet (POE) managed switches have the same “power budget” in other words, you may have 48 ports in a POE switch but it can only power 24 POE devices due to the consumption needs of the devices. Take into account what the switch is going to be used for and determine the cost versus features that you need.

Take a look at these Cisco educational articles:

• LAN Switching
• Intelligent LAN Switch Adoption Considerations