How to use Tape Saturation plugins

So I’m done watching Charles Dye’s Mix It Like A Record and I was surprised at the fact he uses Tape Saturation plug ins on everything. Master fader included! I do love the effect the plugin has on his tracks and I’m embarrassed to say I haven’t paid much attention to them until now.

I’ve done my homework and found some good comments about Voxengo TapeBus and others so I guess I’ll get it soon, but my question is how do you use this kind of plugs? Dye uses tape saturation a lot but he doesn’t really explains why he sets the plugin’s parameters the way he does… so how do you use it on guitars, drums, vocals,… and when? Always, only on more aggressive tracks? Anyway, pretty much any pearl of wisdom you are willing to share will be much appreciated.

Thanks!