I like that gathering supplies is not a challenge in a typical game. What it does do is keep you moving forward. If you blow a couple of days using support spells to explore parts of the world you've already picked over, you won't gather anymore resources and you might feel pressured to go explore somewhere new. I think my party has enough for about a week of camping right now, but I've had plenty of experiences where it made sense to stop for the day because the next bit would be a big push, even though I had only used a couple of spell slots.
In my opinion long rests should not be so punishing that the player feels like they can't use short-rest resources in every encounter, which currently means you should feel comfortable using about a third of your daily rest resources.
