Depends on the available resources we have, About four to six reverbs/effs for about 32 + tracks, each tracks has own sent/returned/inserted Aux-eff parameter. Let\'s say with 6 Aux-eff (Aux1~Aux6), they would give you the total of 64 combined-parameter, with 7/8 aux-eff is about 128/256 combined-parameter and so on.
In addition to adding ambient effects (room/hall simulation) to a mix, reverb is also used to add \"depth dimension\" to a mix. If you want to place certain instruments further in the background of your mix (rear area of stage), you apply more reverb to those particular instrument tracks. If you want to place certain instruments closer to the front of the mix (front area of stage), you apply less reverb to those instrument tracks.
A stereo mix is three dimensional....panning places instruments anywhere from left to right, and the degree of reverb places instruments anywhere from front to rear.