That is a tough question. When should you resign? Some people hate resigning, but in some situations, you must know that you will lose. So what do you believe is the proper situation to resign? I personally think..
Once I'm down material (2 pawns+) and without counterplay I'll resign. I will also resign after hanging a piece.. which I seem to do strangely often on this site, guess it's just a matter of getting used to the look of the site.
Being down in material isn't always bad. Position is worth more than material, you can be down more than a rook in material and still have the upper hand.
If you wanted a answer for the question then no not really, I don't like resigning and usually don't until I can't see any posibility to even get a draw.
As I am playing better players, I am finding that I am resigning more often. I only like to resign when the checkmate is only a few moves away and the opponent has made it clear that he sees the checkmate. There have been a few times when I should have been checkmated, but the opponent made a mistake and I was able to get a draw or a win (ganted these were players below my rating).
I dislike being pressured into resigning, especially when I don't see the checkmate yet.
queenie .offcourse he should have accepted the draw. No doubt about that.
general CC ettiquite at the higher levels (1800+ i'd say) usually means resigning if you hang a piece accidentally.
Either way though, resign once you know your game is lost.
edit - there are two 'exceptions' in my books..
1- Don't stall and hope for a time out, don't stall at all for that matter.
2- If the game is drawn and your opponent offers, accept it.. playing on is frustrating, time wasting, and unfair (being as in real life a tournament director would force the draw).
No you don't know when to resign, or No you don't resign?
I am asking this question since on Saturday, my friends and I played a small simul (4 boards) vs a 2600. I was the only to resign, as I was down a rook. None of the others resigned, yet they were in just as bad situations or worse (5 pawns vs nothing, royal forks)
OTB vs. GM's might be a little differen't.. they don't really expect you to resign and they are by some standards already wasting time so why worry :P.
I would have resigned too... actually, I resign and draw extremely early in most of my games.. it's a bad habit.. I just don't like playing once the position starts getting 'boring'.