Preparing and Casting Spells The Wizard table shows how many spell slots you have to cast your spells of 1st level and higher. To cast one of these spells, you must expend a slot of the spell's level or higher. You regain all expended spell slots when you finish along rest. ...
The point of preparing spells is so you have to do a good job at well preparing for the tasks ahead. The point of retraining skills taking a long time is so that you can't just do it to always match the tasks ahead. For some reason I'm sure you wouldn't be fine with the lvl ...