Since the argument for tri-band routers is bandwidth distribution....

[Simba501]

How many devices on 5ghz might warrant tri-band versus dual band?

Discuss.

 

[RMerlin]

Depends on what kind of traffic these devices do. Having 10 smartphones won't require the same amount of bandwidth as having 5 computers all transferring large files. Those 10 smartphones will be fine with one single AP, while having 5 heavy users might benefit from spreading them between two APs.

Same if you have two low-speed 802.11n clients and two high speed 802.11ac clients - you might want to have two separate APs to separate these, so the N clients won't slow down your AC clients.

So there's no specific rule, it's situational.

 

[Trebuin]

I actually dedicate one band for my extender.