How long do you rest between attempts?

While bouldering inside?  While doing moderate bouldering versus projecting?  Inside versus outside?

I've heard two different rules of thumb for resting while projecting; at least 1 minute per hard move attempted, and at least 5 minutes between attempts. I've seen more than a few very good climbers even set alarms on their phones to enforce this. 

Usually for me in practice it depends on how strenuous the moves are and why I failed. If I mixed up my beta or got out of balance I might hop right back on, but if there is a super-powerful crimp sequence I couldn't quite pull or something I might rest much longer to make sure my fingers are at 100% before I try again.

I don't know if there is a real difference in these "rules" between inside and outside. 

Just long enough to throw a minor tantrum and complain about how scrunchy the move is or how dumb heel hooks are.

It depends.  If my last go I discovered or unlocked something and I'm really psyched because of it, then I'll probably rest just long enough to where I think I'll have a good next attempt with new beta.  If my tries are getting less successful, then I'll probably quit for the day or get on something else to cool down.  There's a whole spectrum in between those two.  Honestly, 90% of my rest time between goes is watching other people stronger than me on the problems I'm trying to figure out.  So, it varies based on the problem and the circumstances.

Ben, those seem like very reasonable guidelines to follow. I probably fall on the longer end of the spectrum as I often find myself resting for 5-10 min between attempts if I am projecting a hard line. If I am super warm, like after one hour of training then I might actually rest less. BUT, sometimes I will rest 10-15min for max effort proj, probably way too long but I lead a very boring life. 

I agree that it is very helpful to watch stronger folks crush it. I actually feel like I have learned how to climb most by watching other people somehow. 

Four years.

Depends. If I take my shoes off, the rest is going to be at least 10 min. :) If  I don't take my shoes off, then about 2-3 minutes

Are you training to rest or climb? 

Outside you should rest long enough for your friends to discover all of the beta.

Saves skin, and if done subtly no one will notice.

10 minutes for proj send burns, less when working bete

For a higher intensity indoor/board session, I'm resting at least 2m and usually 3–5m (with a timer, otherwise I'll hope back on every minute). If it's a long session, I'll sometime take a 10m break in the middle for a snack and water. For interval training, obviously it's whatever is called for given the problem duration.

Outdoors, I've had better results with much longer rest periods. I actually just had a session where my best go came after 20m just walking around with the intention of leaving afterwards, which turned out to be enough time for my skin to cool. But in general, I'd say at least 5m for any non-trivial problem, with no reservations extending that to 10–15m if that's what I need to commit.

I set phone timers in both situations. My natural sense of rest time is roughly five “perceived minutes” per one actual minute, so I need the phone timer to avoid rapid firing.

For what it's worth, although I take much shorter rests when working out beta I'm not sure that's optimal. I think I need to work on that, as I have a tendency to rack up fatigue on attempts that don't produce a send or much useful information, which is obviously a huge waste of time, skin, and energy.