at times my internet stops working and i have to switch my router off and then on. am not sure if this is due to it being old (~5 yr) or that there are several devises connected to it (laptops, phones and ipad) 6 in total.
I have the same problem at work and at home. The problem with the work router is usually corruption of one of the internal tables on the wireless side, probably the MAC address or IP table. I am assuming it's a wireless router?
The problem also occurs at home, but I have a second problem at home, it keeps dropping it's ADSL line and the fastest way to get it to re-sync is to switch it off and back on.
First thing to do is when the Internet goes down is the Router still accessible, try it's webserver in a browser. If it's the ADSL service you might want to check the routers status page and then raise it with your ISP.
I haven't found a good way around the problem, except to restart. We do implement watchdog routines on our automated equipment at work which detect a failed ADSL connection and perform an automated restart, but you need something that will implement this and it is usually easier just to restart.