I never understood more than one instance of a reverb. The whole point is to put the music in a space so why try to put the music in so many spaces?
I agree with this, actually. There are 2 reasons I've been using multiple instances of BREVERB.
The first is that BREVERB has some effects that go beyond simple reverb. Some sound more like a delay, others reverse stuff. I wouldn't want to apply those to all tracks, so keep them, as individual track FX.
The second reason is that even when I use a "normal" reverb, I like to have different amounts of reverb on each track (e.g., lots on piano, little on bass). For me the easiest/fastest way to do that is to put a separate instance of the reverb on each track.
I suppose the proper thing to do would be to put the reverb on a bus, and then adjust the send amounts on the individual tracks. However, I've never gotten used to the routing involved for that; do you have any examples?