the server will never run out of IP addresses, so long as the number of valid certificates doesn´t exceed the size of the IP pool
The server will never run out of IP addresses, so long as the number of
clients doesn´t exceed the size of the IP pool.
The size of the pool determines the number of clients.
However it is not linked to certificates (or the number of), you have to manage that.
A CA can have 1000 certs even if the pool can house only 252 clients (--topology subnet and /24).
Removing old clients also means delete their ccd file and add new ones for new clients.