When is resignation acceptable?

When is it okay to resign and when is it considered poor sportsmanship? It's obviously not okay to resign if we get our queen snagged early in the game, but when it comes to the end game, are we supposed to stay in it as long as possible is hopes of a draw or a stalemate, or should we just resign??

When someone attempts an early queen attack and they lose their queen, they are allowed to resign, but it is poor sportsmanship, same goes for someone resigning when their first attack fails, I'm more interested in the etiquette of end game resignations.

A rule of thumb is to resign when you think there's no reasonable chance at all for you to save a win or a draw from the position. Make sure there are absolutely no tricks/swindles available to potentially save a win/draw, and make sure that your position is actually lost (you don't want to accidentally resign a drawn or won position). The following factors are also important:

Strength of your opponent 

At your level, I think that you shouldn't assume your opponent knows how to checkmate with just king + queen vs king or king + rook vs king. At an intermediate level, you should probably resign if you are in a lost king vs king + pawn endgame and with a king vs queen king vs rook checkmate, and at an advanced level you should resign if you're against the Lucena Position and if you're a rook or more down in the middle game. At an advanced level you should also resign if you're 2 pawns down in most endgames (with exceptions that both the advanced player and opponent should know such as rook with a and g pawns and opposite colored bishops).

Note that that's very little scenarios at your level. I think that you should never resign at this level; the only checkmates that you can be nearly 100% sure your opponent knows how to do is the ladder checkmate with 2 major pieces, and playing on won't be for that many moves so it won't take that much time (plus they might accidentally stalemate you if you're that much up in material). Resigning is way of saving time where the outcome is clearly decided, and at your level in most cases you either don't save time or the outcome is not decided. There's too much chance your opponent will accidentally stalemate you.

How Complicated the Position is

More complications = more opportunities to swindle/come back. Rarely resign in the early/middle game. Maybe resigning in the middle game if you're down a queen and your opponent is advanced, but otherwise the chance of coming back is high enough for you to not resign.

Some games are lost but are very hard to play. Examples are queen vs rook, and 2 Knights vs a Pawn. With these scenarios, do not resign.

Potential Traps

Don't resign if you see any way to save the position at all, even if it involves a mistake by your opponent, assuming that mistake move that you hope your opponent will play looks plausible at first glance. These are called swindles. You will learn these traps as you get better at the game, and I think giving examples of these traps is beyond the scope of this discussion. 

Time

The less time your opponent has, the more chance he has of erring/running out of time. Never ever resign at blitz/bullet, and in general, never resign if your opponent is very low on time. Your opponent could easily stalemate you when trying to move quickly, for example, even at the highest levels.

Here:

https://support.chess.com/article/676-is-it-rude-to-resign-or-should-i-play-to-checkmate

It is not bad sportsmanship to resign. Neither is it to continue playing in a lost position

You have the right to resign whenever you wish. It is never considered poor sportsmanship. 

However, until you get higher rated, you should aim to play on in order to learn more, including how to complicate "lost" games.

Thanks for the info

When the win is obvious you should resign, but when playing with low rated players you should never resign anything can happen.

This is very helpful, from now on I am going to stay in the game as long as possible and try to force a draw or a stalemate.

Resignation is always possible.

Ever thought that chess is about winning? Clearly, stay within the rules but don't worry too much about etiquette, the number of games I have blundered in won positions!

Resign whenever you want to.  But at your level I would always play on because you never know what can happen.

Resign when you want to. Your opponent certainly won’t complain.

BIZMARK, I have respect for opponents who stay in the game against all odds, I want my opponents to feel the same about me.

I've seen more than a few players who don't respect that and will try to queen all their pawns etc if their opponent doesn't resign.  It's always amusing when they accidently stalemate their opponent this way though.

Riverwalk3, I forced a stalemate by leaving myself no legal moves https://www.chess.com/analysis/game/live/19512731613?tab=analysis

Wasn't really a forced stalemate considering the guy chose the ONLY legal move on the entire board that didn't win!

That being said, I agree that at that rating level, there's no harm in playing on for as long as you want as these things will happen more regularly than they should.

Forced is propbably not the best word for it, I was actually trying to move my king repetively and cause a draw that way, but I'll take it how it comes.

Well done.  Playing on in bad positions (especially early on, on a novice level) will force you to be as resourceful as you can. Sure, you will need a lot of luck, but the main benefit will not be a half point here and there. The main benefit will be the fact that you will gain some experience and you might stumble upon an idea or two which might be useful outside bad positions as well.