2 hours before* 
FWIW, I really only use the planner to give myself a rough idea of what my week might look like in terms of intensity/hours, planned recurring rides, etc. More often than not, I end up removing all the planned activities anyways and go for the day-to-day approach that allows for some last minute adjustments based on how I feel, HRV, etc. (similar to @ridgerider2 ).