I have a Linksys WRT54GS Wireless router running DDWRT.
Over the last few months have noticed that when visitors come to stay they can't connect via wifi.
They are using the correct key and can see the network, however the connection fails.
I've checked DHCP and this is set to 20, with only 3 other devices usually connected. Usually a re-start of the router then waiting for a few mins fixes it. Possibly the router is getting tired? Interference? Something else?