I do a few layers of mandatory automation on every mix, then whatever else is necessary for balance, then a layer of creativity.
Mandatory layer would be:
1. Automating the crashes in the OH/cymbal tracks so they all come through cleanly. Automate the kicks so they punch at necessary points (top of riffs, break punches etc.) Automate the room mics in an out of sections depending on the track.
2. Automate the bass for consistent volume/level.
3. Gtrs I automate their panning and level section.
Balance layer would be:
1. All the vocal levels against the track
2. All the groups against the vocal.
3. Any master fader automation.
Creative layer would be:
1. All vocal fx. dipping and raising vocal dly's, automating a dly into a verb, wierd panning and pitch fx...whatever it takes.
2. Any drum filtering or guitar filtering.