Here's a good one...

We run a network for a large museum, and one of the things we recently implemented was an aerohive WiFi deployment with about 32 APs. Since they tend to have large events sometimes, we have allocated a /22 for the public internet traffic. My question is, is this too large of a broadcast domain? I've heard that the rule of thumb is 255 hosts per subnet to keep broadcast traffic manageable, but I guess this is largely dependent on the hardware that is being used. Is this still the norm? Or are there better ways to handle large subnets/hosts on a LAN.

Thanks.