Do the other Spektrum transmitters (DX6i, DX7, DX8 etc.) only need to be bound once to each plane?That is, once they've been bound to a plane, if I used a different plane, and came back, I wouldn't have to re-bind?

Forgive my newbie-ness, but I've got a DX5, and I assumed that you ALWAYS had to re-bind when you switched from one plane to another, no matter which transmitter. If that's not true for the other ones, that might be the push it takes to get me to upgrade.