I suspect, this may be far too common for anyone who lives a "checkpointing" style of life, i.e. once I achieve this, I will pursue this ambition.

I've realized this sort of checkpoint-based planning is not helpful for the long run because naturally, times change, and with that ambitions change. If you haven't already had a taste of making progress towards the said ambition, and it happens to require a distinct set of skills, it becomes quite a mountain to climb.