If there is noting wrong with your binding, then you don't need to switch it it
, but if you feel that your ability has outpaced your current binding, then it's time to get a new one. There are a lot of things to think about when buying a new binding, and you should make a mental list of what kind of features you want.
Stiffness? (you generally want to match the stiffness your board with the binding. if your board is medium stiff [right?]then you would want to get a medium stiff binding to go along with it [so you can to some park, some groomers and generally have fun all over the mountain.])
Customization options? (for the binding to really fit the boot,you may have to fiddle with the binding a lot, and a lot of simple, good tools for customization are optimal.)
Durability? (although paint scratches are merely cosmetic, major malfunctions on the binding are not only costly to replace, but dangerous
Canting? (a wedge that is put underneath your boot to make it more comfortable on your knees, among other things. Some people say if you don't have a wide stance it doesn't matter)
Other tech? (Such as descendable highbacks [for easy strapping in], mini disks on the bottom [for more board flexibility], and other thousands of things binding companies make to suck your money away).
Overall, just be happy with what binding you have, or get, and make sure the binding fits before buying!!!