If you have quality high-cost recording equipment than you probably will not use any noise gate during recording process,because with good equipment noise to signal ratio is already good.If you are using cheaper mics,or fx-procesors for direct recording via line-in than using a noise gate is bad idea again.If you record your vocals or guitar without noise gate than you can later remove that noise very well by using some noise reduction software (that in cool-pro works best i think),and for that purpose you need some portion of sound with only noise heard which enables software to distinguish between noise and signal.If you are using noise gate,you can't than use noise reduction software.And as an collateral damage vocals are much more essed than without gate.I mean "love song" becomes "love ssssong"