Don’t be too vague with the thing you’re working on right now. Be specific and pay attention to details.
When you’re planning for the future, be vague and flexible.
Planning details for the future is like trying to pick which cloud your rocket to the moon will fly through. You don’t even know what will be there and it’s a shot in the dark.
You over-commit and you create a very rigid, very breakable system that will not have the vital agility that projects need.
Specific and details at the moment, but vague generalities (leaving room for creativity and maneuvering!) for future plans.