Is my product still worth keeping?

If it's working for you currently and your not having any problems with it. You can keep it. However older modems and wifi will be come outdated and the ISP speeds your ISP provides maybe not supporting by the modem so thats one factor. Wifi, is always growing and is improved on newer modems or wifi routers. Also be aware that some ISPs may not update cable modem or modem gateways. So you may want to consider getting a modem only unit then attache a exteran wifi router for more control over FW updates and flexibility in management and maintenance of the wifi router. If your ISP does support user owned modems and FW updates then modem combo units are an option.