So I have an Arris Surfboard modem and I've had it for about 3 years and have not had a single issue with it. Over the weekend my internet suddenly cut out and I couldn't figure out why. I had a strong connection and full signal strength on my wifi, however whenever I tried to open an app on my phone/tv/gaming device or browse the internet via my laptop it would say something along the lines that it wasn't connected to the internet or couldn't establish a connection.

I assumed it was some kind of issue with my ISP so I was finally able to get a tech to come out and look at it. The only solution they could offer was to give me one of their rental router/modems, which I don't want to do because I have my own equipment. Once they set up the new router/modem my issues were resolved leaving me to suspect there is an issue with the modem?

Is the modem the likely issue? Is that the expected lifespan of a modem 3 years? How can I troubleshoot this to find the exact issue and generate a different solution? Any advice would be greatly appreciated!