yeah but that is an issue too... if we have 3 encounters that everyone (caster and noncasters) use skills quick thinking and RP to get through then those 3 encounters don't cost any resources... so even an 8 encounter day is only useing the resources of a 5 encounter day.
But how is it an issue? So what if they only use resources on 5 out of 8 encounters? The resources are there to be used or not as needed, aren't they? Nothing says resources need to be exhausted prior to resting.
Most of the time, PCs in my games will have resources left over when they finish a long rest. This is because the players have learned to keep resources "in the tank" so to say because they
NEVER really know if there will be another encounter before they finish resting or not.
This is why I prefer encounters based on the narrative. In tonight's session, the players began with their long rest because of where we left off last time. IIRC the Cleric had two 1st-level slots, the Druid a 1st-level slot, the Sorcerer had a 1st-level slot and a sorcery point, the Warlock had two slots (having finished a "short rest" during the long rest prior to play starting), the Paladin had two 1st-level slots, and the Barbarian had one rage remaining. Now, this was after finishing a traveling for a day and dealing with two combat encounters in the prior session.
So, the PCs dealt with the exploration challenge to find a place to rest, dealt with the combat during the 3rd watch, had to move to a new location and entered a keep, had two social encounters, had to restart their long rest due to all the interruptions, and then had a final social encounter before ending the session.
As resources dwindle, the need to rest becomes greater and greater because the relative strength of the party continues to decrease. But by having rests happen when it fits the story, it is more organic and real, less "gamey" IMO.
Over all yes, but two of the five players were definitely more out of the loop than the other three. However, I know this is more because those two players enjoy combat more, while two of the three others enjoy role-playing more. Last session was more exploration and combat, this one more social. I try the best I can to keep things balanced in the sense of keeping it all interesting to players so they enjoy themselves more.
However, I don't worry at all about balance as far as encounters are concerned. Sometimes encounters are cakewalks, other times the PCs need to retreat. Some adventures have a chain of combats, making rest impossible and the situation becomes desperate. Other adventures involve a single combat or none for several days in a row. Exploration is harder IME unless you want to track things like food, exhaustion, etc. which I know a lot of groups don't. I don't mind tracking it and having players make rolls for exhaustion. Last time I ran RotFM, a PC died due to exposure to the cold (I house-rule cold weather clothing grants advantage on checks vs. cold exhaustion, not immunity to it!).