When that equals just under $0.12 cents per day, when it covers ANY issue that the modem may have (firmware lockups, surge's on the line, "power users" who tinker and hose their modem, etc.)
Your touched in the head if you really have nothing else to complain about, given that its far cheaper than other modem rental fees.
But hey, I guess $0.13 cents buys a lot these days.