This year I've played Xenoblade Chronicles: Definitive Edition and Tales of Graces F, two huge RPGs that feature significant 'epilogue' content. I define epilogue content here as story that takes place after the main game's story and is intended to elaborate on that story in some way. It's distinct from 'post-game' content, which can just involve side quests or purely gameplay based challenges like a "bonus dungeon," or additional but unrelated content like Red Dead Redemption's Undead Nightmare campaign.
For Xenoblade Chronicles I tried the epilogue as soon as the game came out but was feeling burned out so I put it off about 3-4 months and then went back to it. That was fine, and it had the bonus of making me want to revisit those characters and that world again, but it also meant that some of the references that the post-game content makes were a little fuzzy. That game is full of plot and characters and a lot of the NPCs sort of look similar, so I had a lot of "wait who is that again?" type experiences. Nonetheless I had an okay time with the epilogue as a sort of mini-sequel and it was nice to spend a little time with Shulk and Melia on the Bionis again.
For Tales of Graces F I've been playing through the epilogue immediately after the main game, since I didn't feel as burned out, but a lot of it feels like it would resonate more if I'd given it some time off. The epilogue takes place about a year after the events in the main game and there's a lot of the characters being excited to see each other after all this time and talking about what happened to them. It's hard to relate to that because the events of the game are so fresh for me so it feels like it's too soon for nostalgia, and I'm not excited to see characters I was just playing as again.
Both Xenoblade Chronicles: Definitive Edition come with their epilogues already on the disc (or cart in Xenoblade's case) but of course epilogues are sometimes offered as DLC that aren't released until months after the main game. However here I'm obviously asking if you get the package as a whole at one time, do you space out the epilogue stuff from the main game or just jump right in? Spacing out gives time for you to miss the characters and recover from any burnout that happened towards the end of the game (which is common for me in long RPGs especially) but also means that you may forget the mechanics (it took me a couple hours to remember how to play Xenoblade Chronicles properly) and some of the story details. And of course you might never get around to it. Playing right away means your skills at the game are honed and the world is very fresh in your mind, but the nostalgic "we're getting the gang back together" feel of the game might not resonate.
Some of this applies to sequels too. I played through all of the Assassins Creed Ezio games within a few weeks earlier this year and I might have enjoyed the later games in that series more if I'd had time to start to miss Ezio (I could never miss Desmond, of course) but with sequels there's usually a whole new adventure to focus on and a whole new cast, while epilogues tend to be more reflective and less intense.