Help me with my internet?

So my internet lately has been going out non stop (Normally at night) and I'm very sick of it, Every time it does I have to get up and unplug the modem and the router and let them both restart. Then after it will come back on but then go out again in about 10-20 minutes. My set up is an (sorry don't know the year's only the models) Arris Modem and a Cisco router. Also its not windy or raining when this happens. The only people using this internet is me (On main computer) and my brother on his laptop. Sorry to keep going on but i go through Wave Broadband and every time I call them and ask for help they want to send a guy out here to look at it and I wanna avoid that. Any idea's on fixing this? Thank you for your time.