That's because most routers are garbage. General rule is if the case is plastic it will be unreliable 
I see people here spending £200+ every couple of years on the latest prosumer router, it's much more sensible to separate out the functions of wireless access and routing, and just keep a stable platform going. I have a Sonicwall NSA 220 handling things and it's rock solid.

I see people here spending £200+ every couple of years on the latest prosumer router, it's much more sensible to separate out the functions of wireless access and routing, and just keep a stable platform going. I have a Sonicwall NSA 220 handling things and it's rock solid.