I swear, as soon as I say consequences to taking too many long rests, people immediately assume I'm talking about quests with time constraints. I'm not talking about the typical, "If you don't do this quest in 3 days time the quest locks you out and you can't complete it, so move your butt or else," kind of thing.
I'm talking about standard DM logic. I, as a DM, would never want to lock players out of story quests and such. However, if they abuse long rests, I might make things slightly more complicated for them because they were doing things which didn't make sense in terms of the story.
Here's an example outside of BG3 of what I mean. Diadell and her companions learn that there will be a meeting between a lacky of a crime boss and a dwarf who is looking to pick up his money from a job he did. The meeting is to take place that evening, at midnight. In between, Diadell and her companions ran into a few fights, and they don't want to go to that meeting with next to no HP and spells. So, they decide to long rest. "Screw it," says Diadell. "If we miss the meeting, we miss the meeting. I'm not risking it."
So, not wanting the players to miss out on that opportunity, I, the DM, have an NPC friend of theirs arrive at the inn the next morning. "You aren't going to believe this," the NPC says. "I was in the slums at the meeting site where that lacky of the crime boss was supposed to meet with that dwarf who did that one job. There was a rival gang fight, and the whole thing was botched. Looks like the meeting is rescheduled for tonight. Thought you might like to know."
Suddenly, though they did something that should have messed them over so they couldn't complete the side quest, I, the DM, made it so that something happened to explain why that certain thing didn't fall through and so that they know they could still complete the quest. However, because of the rival gang fight, as a consequence for not going, I make it so that there are more gang members at the spot because they are expecting that there could be more rival gang trouble. Whereas initially, the encounter might have been easy, I make it slightly - SLIGHTLY mind you - harder to compensate for the fact that they decided to long rest. I originally built the encounter expecting that they would be weaker, so it wouldn't have been as tough. Now, however, because I know they are going to be tougher since they long rested, I increase the difficulty of the fight to make the battle more fun and rewarding.
Right now, the issue is that long rests in the game without consequences like this make every fight easier. That's not how good DMing works. If the players are going to long rest frequently, then there needs to be some sort of complications and such that make up for the fact that they decided to reset all their HP and spells and such.
