Quote Originally Posted by Buffalobiian View Post
Regardless of whether you "learned" it or not, the effect is instantaneous as far as we know. That wasn't the case for Netero. He was gracious from the start of his training but the effects didn't manifest until long afterwards.
That's because when he started his training, I don't think Netero even knew how to use Nen at all. There's nothing that really suggested that he did. None of the people in the Dojo's he went to afterwards seemed like they knew how to use it.

Adding a restriction may have an instantaneous effect, but learning Nen from scratch with no teacher isn't. I think he simply taught himself to use Nen with a restriction applied from the very start.