what to do with rythm guitars when leads come in/out?

1) Do nothing with the rhythm guitars when the lead guitar comes in and make the lead louder than it should be
2) Automate to slowly reduce the volume of the lead and rhythm guitars after a few seconds until everything is "right" again.
3) When the lead guitar ends, emphasise the next riff by making the rhythm guitars louder than it should be and then reduce the volume again

That way you direct the listener's attention towards the lead guitar by making it pop out and to the rhythm guitar after the lead is done.

Even mixes are horribly boring. Don't make them!
 
1) Do nothing with the rhythm guitars when the lead guitar comes in and make the lead louder than it should be
2) Automate to slowly reduce the volume of the lead and rhythm guitars after a few seconds until everything is "right" again.
3) When the lead guitar ends, emphasise the next riff by making the rhythm guitars louder than it should be and then reduce the volume again

That way you direct the listener's attention towards the lead guitar by making it pop out and to the rhythm guitar after the lead is done.

Even mixes are horribly boring. Don't make them!

Agree

conidering sidechaining a ducker on the rythms with the lead as feed also works :)
 
Depends on the musical style; in seventies rock / hard rock i usually dub the lead guitars and hardpan that LR; leaving a single mono rhytmguitar in the middle. In metal I try to leave them untouched and get a lead sound that cuts through well. If doing big multiple harmonyguitars (like 3 tracks or more) I usually bring down the rhythm guitars a bit.