For new customers, Optimum offers a complimentary Gateway modem-router device with most plans. In contrast, existing customers are charged a monthly leasing fee ranging from $4.95 to $9.95 for the modem-router. If you're an existing customer, you have the option to purchase your own modem-router, but it's essential to verify its compatibility with Optimum's network before making the purchase. If you intend to remain an Optimum customer for three years or more, the device will essentially pay for itself, unless you opt for a high-end model. Many customers prefer this approach as it affords them greater control. However, it's worth noting that the typical lifespan of a router is between 3 to 5 years, so you may need to consider a replacement within that time frame.