How long would a character be an apprentice wizard?

This is something I've always wondered about. The fact that human wizards start around the age of twenty implies that it isn't terribly long- likely ten years, at most.

I ask because I have recently taken it upon myself to write a story, and the main character is starting as an apprentice. I need some general idea of how long that phase of life would last. I'm thinking two to three years, just for story purposes, but I want to get an idea what others feel is reasonable. In addition, I'm struggling to figure out a timeline for that- when would he cast his first cantrip, his first first level spell, etc. Any suggestions?

Training times conform to plot. It depends on several factors; high magic or low magic? War or peacetime? Long lived or short lived race(s)? How does one graduate to the next level (what are the levels?)?

The lower the magic setting the less chance of their being magical apprentices, and the shorter the training period (think Star Wars IV and Luke's timeline for training to be a Jedi). Similarly war (and other push factors; disease, personal motivation) will have a significant impact - this is covered under personal motivation (liches, sith lords, Luke). Longer lived races have the time to truly master their arts, and better understand (often from personal experience) the effects of incomplete training (Anakin vs Yoda). Lastly it depends on the upper skill cap, and the average skill (and availability) of those doing the training. This ties back into high vs low magic to an extent, but can be setting specific to a smaller part of your overall world.

Were I designing a setting, magic users would look something like this:

They are born with certain strange abilities which manifest through their childhood. Doors open or close mysteriously around them, spills leave their clothes unsoiled when they consider what their mothers will do to them back home, things sporadically catch fire around them (this one could be fun plot-wise). I'd pick a single cantrip and design a mini-arc around it. As they get older they get more in touch with this strange power, and introduce generic mentor. Initially it would take a few years to master using their cantrip, and expand their list of cantrips suitably. Finally they'd learn their first first level spell. For a book I'd make that plot dependent.

Also, consider that training times would include learning skills broader than magic. Learning different philosophies, mathematics, and Physics would all play a part in training to bend reality to your will.

Hope that helps.

Like most Professional programs after grammar school, it should take about 3-5 years.

The first 1.5-2 years would be completely didactic with no actual spells being cast. Then the remaining time would begin to introduce the cantrips one at a time and recitated until mastered.

They would begin casting first level spells just before coming on screen as a first level character.

I feel like as a first level character in s PC class that you should no longer be an apprentice but instead be considered a journeyman.

This is something I've always wondered about. The fact that human wizards start around the age of twenty implies that it isn't terribly long- likely ten years, at most.

I ask because I have recently taken it upon myself to write a story, and the main character is starting as an apprentice. I need some general idea of how long that phase of life would last. I'm thinking two to three years, just for story purposes, but I want to get an idea what others feel is reasonable. In addition, I'm struggling to figure out a timeline for that- when would he cast his first cantrip, his first first level spell, etc. Any suggestions?

Break it down for whatever story you want to write. That wizard who starts out at twenty may very well have been bought from his parents at the age of five, spending those first five years at manual labor. Or maybe he came in as a teenager, ran away with one of his master's spellbooks, and taught himself.

There are no such thing as hard and fast rules for this kind of story.