It was a long time dilemma at NYGC. Students would complain lost of internet either in the lab or wireless. I would blame it on P2P downloaders while trying to solve the issue. It had gotten worse when staff has to manually power off/on (reset) the router, Buffalo WHR-G125 running on DD-WRT firmware,about twice everyday during school hours.
Yesterday, I came across a site about how WEP wireless security is unstable. So I changed it to WPA2-AES Personal encryption method. Seems fine now. Uptime has been 1 day 5 hours and 42 minutes already.