In reply to RyanR.

Hmm exucse me but Beyonce has never sung an entire tour live. She´s not the best example you could give. Adele has done a tremendous job with her voice in this tour. It looked like a crazy idea from the start to me anyway. She´s only cancelled two last shows. It happens. Whitney Houston is pretty much the only example that comes to mind right now that sang whole concerts and tours live. Lenthy ones. And she performed sick many times. Was it the right decision? I´d say no. I applaud her for keep going, but she was hurting her voice, you could see her hurting face in many I´m your baby Tonight tour dates for example. She was very sick.
No, Adele has not the stronngest of voices. But over 100 LIVE dates is crazy for any voice to be honest. Leave Beyonce out of this because she truly can´t relate :)