Where are you storing your line (& reels) when not fishing with them ?? I've got spools of line that are over 20 yrs old, and still good ... they stay in my fishing equipment closet (climate controlled). Sunlight &/or heat will degrade mono over a fairly short period of time. That's why line & spooled reels shouldn't be kept in your vehicle or boat or tacklebox for extended periods of time.
As for biting the line ... an el cheapo pocket knife will take care of that, and probably save you a few trips to the dentist. A pair of Childs Size Fiskar Scissors (<$3 @ WM) is your best friend, when it comes to cutting braid. Just don't go grabbing it, wrapping it around your hand, & pulling on it to free a snagged jig ... it'll cut you quick !! Best to have a towel or dowel rod to wrap braid around, for that situation. It'll cut cork & foam rod handles, too ... so I don't recommend trying to use them, either. I know all this from experience

... having used PowerPro 10/2 braid for several years !!
... cp
