We won’t look at how a wizard, shaman, or other type of practitioner spends his day so much as the phases of his career, from how the ability is gained and lost, their training, what life is like at the height of power and then if they begin to lose strength with age.
How the Ability is Gained and Lost
Even if everyone in a setting can perform magic, we must decide how the ability is gained (or lost). Our default is that it’s like talent; you’ve either got it or you don’t. However, even among those who do, they sometimes don’t know it, feel it, or have it until they reach a given milestone. This can be an age or event, such as losing virginity, a first period for a female, or the first time we draw blood or kill someone. Maybe we even need to die and be reborn. Perhaps the ability can be given like a gift under certain conditions. We might have to consume something once or regularly, like a potion, pill, plant, or animal.
What about losing the ability? This seldom gets a mention but is worth focusing on. If magic is a talent, then it theoretically never goes away. But maybe it depends on how the magic works. Songwriters always have the talent to write music, but as we all know, some are better than others and there are times when a band seems unable to write great music anymore. If performing magic requires some originality or inspiration, then maybe some wizards have fallen from grace, their “heyday” behind them. They can still do it, but they’re out of ideas for new actions. They’re the equivalent of a “has been” band still touring and playing their greatest hits.
If an event causes magic ability, can another make it stop? Maybe a potion, pill, plant, or animal takes it away. Perhaps someone must be celibate like a priest; this raises the unfortunate prospect of rape being used to render a wizard non-magical. What if killing someone, drawing blood, or another act causes the ability to weaken or fade? The gods can make this a reality to punish people, particularly if magic was used to perform the act. A benevolent god might do this, but perhaps a nefarious one grants the talent for causing mayhem.
If the ability is gained or lost, decide if this is permanent or not. Maybe having it was never forever anyway. Maybe the sun gives the ability, but the sun is too far away in winter and wizards cease to be one for part of the year. Do magic items stop working at that time, too? What if an item was holding up a building?