The Problem: After having a router for a while, you notice that every now and then it shuts itself off.
Quick Fix: This is usually caused by overheating. Many of us leave our routers running 24/7. As it ages, the router can become less efficient at cooling. Check to ensure the cooling vents on the router are not obstructed. Unplug the router for a bit. Use a can of compressed air to clear out as much dust as you can from the vents.
Newer routers have energy efficient settings that let you specify when they should shut the wireless radio off or power down, such as after 30 minutes of being idle. If your router doesn't have this feature, best practice is to turn it off when it’s not being used, to extend its life.