My personal theory on “take-backs” in tabletop games. If:
(a) There is no new information; and
(b) the game has not changed
Then a move can be changed.
In more complex games, we are also generally pretty relaxed about retconning standard maintenance tasks that get overlooked as long as they don’t impact ongoing events. (So you can’t say, “Oh, hey, I forgot to add a reinforcement to this province that’s about to be attacked.” But it’s probably okay if you say, “I forgot to grab $300 for occupying Yu-Shang.”)
Also important is the difference between may and must in rules. “At the start of each turn you may take 1 card from each player” if missed, cannot be done at a later time (unless it’s very soon after) as anything taking place in the intermittent game time could have had an effect of strategies employed. If it’s a must or implied must “At the start of each turn, take 1 card from each player” is everyone’s responsibility to remember and should have been factored into their strategy.
Also, leniency is often given to newer players and sometimes a player plays his cards/actions a bit too quickly, not giving time for a response and we’ll have to back track. All in all it should be avoided imo.
gaynorvader @ 1 – You may be aware, but the “may vs must” was a bit of a thing in competitive Magic: the Gathering within the past several years. It seems very simple – if you missed a “may” ability, you missed it, no takebacks, and if you missed a “must” ability you had to rewind as best possible to do a takeback – however, there were grumblings from the players who were given warnings for missing a small “must” ability on their opponent’s side, and grumblings from judges who had to untangle games that were thrown into chaos by forced rewinds.
The current solution is that if you miss a “may” ability then you’ve missed it, too bad. If you miss a “must” ability and don’t catch it within a reasonable amount of time (usually by the end of the turn) then it’s up to your opponent whether or not you are forced to rewind back to it. In practice this means you don’t get to re-do your beneficial missed abilities, but you are forced to re-do harmful missed abilities.
This is a good baseline for most games I think, with the caveat of being more lenient with newer or more casual players.