Rune
Once A Fool
How do you prevent too many long rests. How do you allow just enough short rests?
First of all, I don't worry about it. I accept that it is likely that the PCs will only have (at most) one or two combat encounters per day in certain environments. I also accept that not all combats are meant to be challenges. Sometimes the pace is better served by giving the players an outlet for badassery. (I also don't tie leveling to combat, which is not necessary, but helps me establish the play style I like). Sometimes the combats will be overwhelmingly difficult. I don't worry about their resources.
Instead, I try to give them hard choices, which sometimes include balancing whether or not they should jeopardize the accomplishment of their goals in time against the possibility of failure through attrition of resources. Because, running a sandbox does not mean running a game that is in a time-vacuum. NPCs have agendas and they will work toward them.