Really? How did you survive without cleric spells?
Potions and wands, for one.
For two, you avoid getting hurt, even if that means making a strategic retreat or even
avoid a conflict you think would be a close one.
For three, its almost unheard of for the guys running the divine casters to use all of their spells until it actually is time to rest. Last night's session in RttToEE was a perfect example- our party of tenth level PCs had several members down to 2 or 3 HP. We've quaffed enough potions to get those PCs (including at least one fighter) up to about 25HP each. Our casters had only a few, mostly 1st & 2nd level spells left (except the mage, who still has 3 Lightning Bolts).
The last encounter of that latest session was the
6th in the party's day (24 hour period).
Our casters do use their spells...but only when they have to. The mage softens up the foes with a spell or 2 then holds and holds and holds while the warriors do the dirty work...unless a foe needs additional zapping, that is.
Our spellcasters- clerics included-
do not determine when the party rests by blowing all of their spells. Instead, "camp time" is determined by when everyone else is blown, and
THEN the final spells of the day get cast.