Heating

Kenneth Woods makes a fascinating analogy between rehearsing in unheated churches (and otherwise non-ideal spaces) to high-altitude training for athletes--practice in extreme conditions supposedly better prepares you to perform under ideal (or at least better) conditions.

His complaint about unheated churches doesn't take into account that churches sometimes have official policies about heating which sometimes plan to freeze visiting groups in order to save money. This is their choice, although they should be upfront about it when renting the space.

Finally, he says this:

People who run multi-purpose venues often treat the music part of multi-purpose as "allowing musicians to use the building," with no consideration for creating a space where the musicians can hear themselves, or for what the music sounds like in the hall. It's all well and good toughening yourself up, but every musician who puts the work in should get to hear themselves in a decent space. We're far more dependent on the spaces we work in than theatre groups or dance troupes.

His first point there is well-taken, but I doubt that dancers or actors would agree that the space doesn't impact them just as much.