You are impoverishing yourself for the sake of your apprentice. It is their privilege to be your apprentice and three seasons of work per year in exchange for a season of training and the opportunity to graduate from apprenticeship as a member of the order is an absurdly good deal. To put more than a season a year into training your apprentice is from the point of view of the teacher magus an absurdly generous gift. If you have a 0 communication and only collect exposure experience in teaching (specialization apprentices) then your apprentice will be as well or better trained at the end of apprenticeship as a starting character even if they never spend a season in study.
Apprentices are for extracting vis, copying lab texts, making casting tablets, doing tasks that are too trivial for you, and occasionally helping you in the lab.
before I let an apprentice read for a season I'd make sure that there was no one I know who wanted to copy a lab text, that none of my sodales who wished to have an arcane connection fixed, and that I had all of the vim vis that I could ever want. 
Here's my take on the issue from a few years ago.
https://forum.atlas-games.com/t/napkin-scrawl-apprenticeship-time-distribution/5555/1