Standalone APs will only choose a new channel (SmartSelect) when they are
rebooted, as they don't communicate with other APs. Adding a ZoneDirector
controller, allows the ZD to update the APs with periodic (def 10min) best
channel/power settings, and can adapt to dynamic changes in RF/interference,
that standalone APs by themselves don't. Additionally, Channelfly feature in ZD
managed case, will choose the best of all 11 of the available 2.4G channels, and
improves throughput.
Second thought, does rebooting the client radio/NIC also help with connection
problems? Are all clients on the AP having issues, or just one?