I believe the maximum is somewhere up around 72 Boost WiFi pods connected to a single network. It's an absurd amount for any residential set up. The most I've seen or heard of was somewhere around 30-40 or so that were connected together to provide fibre fed gigabit WiFi to the firefighter camps in High Level during the big fire there earlier this summer.
I was also wondering about the best distance between pods. The Telus site indicates a maximum of 12m/40 feet. Currently I have a distance of about 6m / 20 feet maximum but I am wondering if I need a few more pods to shore things up. My house has a lot of legacy audio wires (from the original owner) that are likely causing interference. What do you think?
I guess it would depend on the size of the house and if you're seeing any WiFi dead spots where speeds start to tank. 3-4 pods is normally enough for a multi-floor home. The best option is to have them all hard wired via cat5 if possible but you can wireless tether a ton of them too. It just adds a little latency and speeds wouldn't be as great as hard wired.