I told my boss about my studying (complete career change) and how I would be leaving at some point. Told him about my last lot of annual leave was for my placements and I’d have enough leave for my next placement but after that I’d probably have to leave.

His response was: Don’t worry about taking leave for it. We’ll work something out.

I was umming and uhhing for months on whether I should tell him or not and decided yesterday to do it because it would then force me to decide how to approach studying/working instead of worrying about it. That went a whole lot better than I expected.