Do I need two wireless kits for my setup?

 The rule of thumb is that you need 1 kit for every MIDI cable you intend to replace. If you are connecting a MIDI keyboard wirelessly for use on a stage, or just wanting to remotely drive a player piano or organ, 1 kit is sufficient.

If you are using MIDI to sequence and play back a synthesizer, or for two-way control - anywhere two MIDI cables are required, you will need two kits.