If its not actively passing data then it's not using any bandwidth, but depends on the application that is running. The bandwidth per user is dynamic and it's not hard set per user.
As for your wireless, what AP's are you using, is it autonomous or lightweight and what code are you running. When devices stay connected like that and you know for sure you have good coverage, you might look at disabling some of the lower data rates to allow for the devices to handoff to another AP. Be careful if your devices are old because they tend to require 1mbps or 2mbps. If they are newer devices maybe disabling data rates below 11mbps on the 2.4 and data rates below 12mbps on the 5ghz if your using that. This you will need to tweak.
Sent from my iPhone
-Scott
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