G. Mark’s Answer
It need not wear one down at all if one paces oneself and actually enjoys the subject. Be aware that leaving school does not equate to leaving hard work behind. If what you study is actually a good choice for you, the work can be enjoyable and rewarding. If you like what you study, you've got a life of enjoyment ahead of you. Not idleness, mind you, but enjoyment. I always loved what I studied and because of that my career, while occasionally very stressful, has always been enjoyable, entertaining, interesting and rewarding. I can't imagine not doing it.