My last post talked about the 5th edition retcon situation. I will take a few paragraphs to share our experience since restarting the campaign with 5th edition.
The shield spell has been the most common retcon. I have two characters who can cast it (wizard and multi-classed paladin-sorcerer). My first concern was me remembering from game to game to behave differently when player characters are about to be hit. This has not been so much a problem, I am learning. Seems whenever those two PCs are about to be hit by something the shield can affect, I successfully pull of the "it looks like you will be hit" or some such phrase and then sit silent staring expectantly at the player for a few seconds. As I had hoped my players did 'get' it fairly quickly.
No player has so far taken the Lucky or Defensive Duelist feats, so I don't have experience there. Therefore I have not needed to change my rolling behind the screen preference. Also, my players roll their own d20s in the Cone of Fate when they should not know the outcome. For example, if I do not want them to know how stealthy they are... or are not.
The most challenging play so far has been the wizard, who is a diviner with the portent feature. So now any attack roll, saving throw, or ability check is fair game for a retcon. The first few sessions had some awkward moments. I first erred by simply saying the outcome, only to be corrected by the diviner who said differently. Next I spent way too much time staring expectantly and then have nothing happen. I eventually settled in to staring expectantly only when something 'big' is happening. I let the little things go by and they rarely get corrected, and mostly the corrections happen when a player makes a poor roll and the diviner sees it differently. These small amount of retcons does not seem to be busting our immersion, especially since the wizard only gets two d20 pre-rolls with each long rest.
So far so good, retcon is not making our game less fun. On the contrary, the shield spell is making them less risk averse, and the portent feature has been jolly good fun when worrisome moment gets quickly turned to a sigh of relief and cheers.
The dice never lie.