Maybe old ones might not support the setting but anything bought in the past few years would have it. By default they’ll come with 100 or 256 enabled (I’ve seen both) and since they re-use connections as machines connect & disconnect, you’ll likely never notice. But I lock mine down to the number of devices I have connected (or will connect - like a tablet that might not be on) and once it hits that, it rejects additional connections until someone disconnects. It’s just one more layer of security. Someone outside could slip on when one of our devices leaves the house, but it makes it less likely that my neighbor’s 10 devices are going to be poaching on my network 
1 Like