I recently switched to Spectrum and wanted to use my old cable modem (purchased back when I had time Warner before the merger), but the installation technician

I recently switched to Spectrum and wanted to use my old cable modem (purchased back when I had time Warner before the merger), but the installation technician told me that they no longer do rental fees for a modem, only a router! I actually didn't believe it so I used my old modem anyways but he was correct when I got around to checking! Spectrum does charge a rental fee for a WiFi router, which seems ok to me but I do wish there was an option to just buy it directly from them.