So many people conflate 'adventuring day' with 'long rest'. I understand why (it's easier to do it that way) but that's what character sheets are for.We simply go from one session to the next without a long rest.
At the start and end of every session, I ask the players for what resources they have left (hit points, hit dice, spell slots, and other finite resources like Ki, SP, sup die and the like).
I also pretend to write it down.
Keeps them honest.