Where do you draw the line on editing?

IMO if you do a good job on a recording from start to finish and the end result is good no one will ask these questions. I personally prefer a bit more of a human feel than a lot of people but that's just a matter of taste. I do what ever it takes to get the job done. If you're really hung up about cleating then you do what I did for years and study classical. Those guys are maniacs. To them anything other than playing a piece from start to finish in one go is cheating, and if you see the lengths they go to to perfect their tone, play every note correctly, your head would spin.

One point I will elaborate on is copying and pasting parts. For years I didn't do this because I thought it sounded better but after a while I realised the opposite is true (IMO), when you play something and it sounds right then the listener is expecting to hear that again. I also discovered that lots of the big names do this. With so many stems available you can easily check this for yourself, often parts sound different in the mix because the drums or other parts are different.

Here's a quote for you:
"I tend to get it a section at a time. Mainly so the tuning stays exactly the same for the four tracks. If I can cut and paste, I'll do that also, the guitarist could sit there and do it again, but whats the point??? If you've got it perfect, why do it again." Andy Sneap.
 
There is an interest in copy/pasting : sometimes the musician looses energy compared to the beginning of the song, typically a chorus can be recorded better than another one, so sometimes copy/pasting the "better" can benefit the song. I try to avoid having anything weird going on the take. Any string noise that your ear can pick will make the whole thing artificial if you can hear it in every chorus in the song !
 
There is an interest in copy/pasting : sometimes the musician looses energy compared to the beginning of the song, typically a chorus can be recorded better than another one, so sometimes copy/pasting the "better" can benefit the song. I try to avoid having anything weird going on the take. Any string noise that your ear can pick will make the whole thing artificial if you can hear it in every chorus in the song !

I have the opposite problem sometimes, where I gradually warm up and get into it, so by the end of the song I'm playing the parts better than when I started, in which case I tend to either retrack earlier parts or copy and paste.

As for the other stuff:

1: Recording parts slowly and then speeding them up.
I really don't like doing this, but sometimes you gotta. I know I've had to slow stuff down myself while tracking, but never more than 10 or 15 BPM.

2: Punching in frequently/recording a couple of bars at a time.
Totally cool with this, with some people I've had to do punch-ins down to eighth notes, no shame.

3: Blending multiple takes with playlists or similar.
I guess just stringing different takes together? Sure.

4: Quantising drums/guitars to tighten them up.
If it's just to improve bad spots in good performances, nothing wrong with it. But if it's to make the performance passable, then I'd rather not.

5: Auto-tuning vocals.
Just as before.

6: Copying and pasting parts.
Totally cool with it, like I said earlier. If a guy gets a hard part down once, no point in wasting time doing it fifteen more times.


In general, I'd rather get them playing each part, without any sort of fancy technological manipulation. But when "the best they can" is bad, then you gotta do what you gotta do.
 
There is an interest in copy/pasting : sometimes the musician looses energy compared to the beginning of the song, typically a chorus can be recorded better than another one, so sometimes copy/pasting the "better" can benefit the song. I try to avoid having anything weird going on the take. Any string noise that your ear can pick will make the whole thing artificial if you can hear it in every chorus in the song !

You should be avoiding too many string noises to begin with, and I think you're probably being a little too picky on that; I would let something like that slide under the 80/20 rule Brian mentioned above, or juggle the left/right tracks so that the noise happening on the left side in the first chorus appears on the right side in the second.