I find that an off-stage mic can give you a huge advantage over a wired mic when the acoustics of the hall are really bad. Here's a telling example: I and two other callers called a square dance at Swisher's hall, known perhaps for having the worst acoustics on the East coast. I called from the floor while the other two called from the stage. At the end of the event about 6 dancers came up to me and said they could understand me but not the other two. When you call from the floor you can hear what the dancers hear. You can change the way you call (more spaces between words, vary the loudness etc.etc.). Doing this doesn't negate the bad acoustics but it does help. For me it's clear: being able to be heard is far preferable to being seen. And I would argue that the dancers (new and experienced) are looking at their neighbors, partners etc. during and after the walk through. Add to this what others have said about helping dancers in distress and I think you can really see the advantages of going wireless. The last advantage is checking the sound (balance of the instruments, balance of the caller verses the band etc.) as Eric previously pointed out. I've been criticized by a few people over the years for doing this. They say the beginners freak out when they can't see the caller. I wish I had asked them how they knew this. I'm assuming they took a survey or more likely, they read minds. Be careful you don't create feedback. If you call off-stage, maybe have a talk with the sound person before the dance. Tom