I think it also depends how often you get a chance to play.
Living in a small population area (central Maine), I have one friend I play face to face. Just getting a weekend now and then to play takes a good deal of effort - between kids and work it is a challenge to carve out the time. So, when we play, we both hate to have a 13 turn game end on one stupid mistake… it took us two months to get a chance to play in the first place…
Generally, our rule of thumb in any situation is… have dice been rolled yet? Would it have affected anything going on in the current turn? Typically, if it has little effect on the game, it’s a “no problem, just remember me when I need a break” and then take a drink, or two, or three of beer.
But if dice have already been rolled, or it’s right on the front and will strongly affect the current turn (“oh shoot, by the way I forgot to leave that infantry blocker in front of your mech and armor stack…”), forget about it.
Sometimes seeing your opponent’s mistake becomes a great reason to hurry up with your own purchase, and combat movement, and start rolling the dice… by then, it’s too late…
And after all, war is often about taking advantage of mistakes.