I'm sure others have disvovered this too, but I thought I'd share a little tip:

Though I work mostly with rock, pop and folk projects, I often use live cello and violin etc. I record at least stereo, but often record Mid/Side plus room, which makes for 4 audio tracks per performance.

In the past it was a pain to fix any intonation issues a performance might have (even the best guys miss a note or two) - you can't stick autotune on every track separately as they all respond differently depending on the nature of that particular source (different mics and distances) - which causes phasing and chorusing.

Since AUX tracks came out, I just submix all the mics to a track and stick Autotune on that track. Works great.
 
Ludwig
 
 

To be fair, you could also do this before with buses, but I agree it's nicer to have the track right next to your sources.

True.

Very handy Ludwig. I must confess when aux tracks were first introduced, given that we already had unlimited buses, in my ignorance I wondered at their usefulness. Now you would have to prise them from my cold dead hands:)

Also nice is that you can record the tuned tracks for archiving. Yes you can bounce busses too, but it gets messy. I love them little Auxes - every day a new use is discovered. And the ProStoolz users have finally run out of stuff to say :O)

I love being able to record aux tracks, definitely!

Pro Stools.

tenfoot
Very handy Ludwig. I must confess when aux tracks were first introduced, given that we already had unlimited buses, in my ignorance I wondered at their usefulness. Now you would have to prise them from my cold dead hands:)

Correct me if I am wrong.  What I like about Aux tracks is that I can use external effects and print to Aux using its record feature.  You can not record a bus track.  For that matter, you can print any effect thus lightening your CPU load.  Very useful.

jmasno5

tenfoot
Very handy Ludwig. I must confess when aux tracks were first introduced, given that we already had unlimited buses, in my ignorance I wondered at their usefulness. Now you would have to prise them from my cold dead hands:)

Correct me if I am wrong.  What I like about Aux tracks is that I can use external effects and print to Aux using its record feature.  You can not record a bus track.  For that matter, you can print any effect thus lightening your CPU load.  Very useful.

Yes - I have discovered that and many other advantages since John. As I said, it was in my ignorance that I didn't see the point. The aux tracks also happened to be released around the same time as the ability to record vst instrument outputs real-time. A golden era of great leaps forward:)

I use Aux tracks to create "safety copies" of virtual instrument audio. So each synth folder has the audio for the synth and a muted MIDI track.