CapnZapp
Legend
I'm not using xp either, like at all. Not using exactly milestones either.The work is primarily calculating XP for the traps or other non-combat encounters, since the system doesn't inherently cover that for you now. There is also more work for a DM like me that doesn't already design my approach using the XP/CR system. In fact, I don't use XP as written at all, making a system like this difficult to implement. But that's really my issue for not using the existing system.
I simply tell the players at the end of a session "you've gained a level" and they can spend the time until next session planning and studying their next level.
I honestly don't see why I/you/we have to do "more work". Not only do I not like work

So what's the work and why do we have to do it?
(Not directing this to you in particular Ilb. I am asking everybody that claims there's a connection between xp and ep)
Why not just run your games as per usual, just winging it "that encounter felt like it was worth 2 EPs"?
Sure, you might end up overestimating some encounters that really should have been easy:ish, but the players bungled it. And you could concievably think "well, that was easy" and give out 0 EP even though it was smart play that trivialized the encounter (and not lack of xp in the encounter budget).
But that mostly points to inexperience with the system - kinks that will be ironed out soon enough, just like how you learn to create encounters on-the-fly without "xp budgets" as you gain experience as a 5E DM.
None of this is suitable for the newbie DM, after all.