I guess your concern will be only when you expand your network.
You must take in consideration if new routers will run on adhoc or mesh mode.
If the devices already existing are running adhoc, you can evaluate if they can be changed to mesh, so you have the whole network in the same mode. If they can't, you could still try to find and add new routers that offer adhoc mode (although they seem to be less common these days).
If you can't upgrade the old devices and can't buy new routers with adhoc, they you'll have to have two different "clouds" connected through ethernet that won't talk to each other on wireless (but will still be in the same network, sharing the exit gateway, ip range etc).