When it comes to 3D Adventure games that have multiple levels to choose from what is your preferred method to accessing them?

1) Unlocking them by collecting a specific number of collectibles?

2) Have a small group unlocked after beating a boss?

Just want to hear your opinions as I'm trying to finalize how the Hub world should be accessed

I'd got for a quest based model - achieve something in gamevand get some new areas unlocked.  That said, I have better things to do than collect junk for the sake of collecting it.