As am I.
Its called resource management, and its a part of any conflict. The archer with 20 arrows makes the same kind of decisions.
Its just magnified in D&D because the foe around the corner may just be a Pit Fiend.
Speaking of resource management - One of the biggest changes to the Wizard between 1e/2e and 3x (and imo probably the biggest contributor to 3x wizards power) hasn't been mentioned. In a "standard" game 3x wizards have extraordinarily easy access to scrolls and wands compared to prior edditions(yes they cost money and xp but a very minor amount compared to the benefit gained).
This means a 3x wizard rarely has to memorize knock, invisibility, protection from evil, tongues, teleport and a meriad of other useful spells. IME this is what took the wizard from a merely strong class to one that towered above non-casters (and to a lesser degree above spontaneous casters).
A 4e wizard has access to scrolls too - in the form of rituals, but the cost and casting time is a significant balancing facter (If the rogue can pick the lock in under a minute whereas the wizard takes 10 minutes has to spend money, and looks ridiculously conspicuous for those 10 minutes, there is actually a benefit to letting the rogue do it).