Just reboot your router like once a week to clear the uPnP tables. If your using fixed IP addresses for most things on your lan then its not a huge problem. I use DHCP, but reserve IP's for all my devices uPnP used to be flakey as fudge and crash routers etc, but most routers less than 3 years old should be able to handle it. I use a 4 year old Netgear WNDR3700, cause I'm too cheap to buy a Nighthawk, and I haven't had any issues with it. Most people use more than 1 thing that uses the same ports nowadays rendering port forwarding useless.