Teacher 1: 9th grade english; 11th grade IB english; 12th grade TOK
Teacher 2: 10th grade math (we were very close and he was my advisor before he retired)
Most colleges prefer letters from 11th/12th grade teachers. Will I be disadvantaged for having a letter from a 10th grade teacher, even though he knew me exceptionally well and liked me?
I don’t think so. If worried, get one extra from a more current teacher.
The guidance counselors at my high school strongly discourage getting a letter of recommendation from any teacher from freshman or sophomore year. You’re not the same person you are as a senior compared to when you were a freshman and sophomore. In my opinion (and from what I have learned in school), it will put you at a slight disadvantage. Choose a teacher from 11th grade or 12th grade. If you really want to have your 10th grade teacher write you a letter, then I would suggest having his letter as a supplement.