Quote Originally Posted by Joshc View Post
Here опять threw me off because I thought again = repeated action, which requires a imperfective verb. But here, I think we want to put more focus on the action which would make sense to use a perfective form. Thanks for your help.
опять - again describe here a one-time action even if similar action was performed before.

Possible meanings of "Завтра я опять буду ложиться поздно" are the following:
1) Tomorrow I will go to bed several times and all of those times again will be late. (repeated)
2) Tomorrow I will be performing my ritual of going to bed late again. (continuous, if the process is more important than the result)

But normally in this situation we speak about expected result of getting to bed, so perfective is used.