According to Wired, if owners want to use the disc with a second account they'll be asked to pay a fee and install the game from the disc, suggesting that once games are installed you won't need to insert the disc to play.
It's unclear what this means for the secondhand market, though Microsoft announced on an FAQ page (since removed) that the Xbox One is designed "to enable customers to trade in and resell games. We'll have more details to share later." It didn't reference the fees confirmed by Microsoft to Wired.
In My Mind of Mr. Mike I believe in full game installs for better game performance and updates, plus think for a moment a slow read of bluray media yep I will install! But what about the hard drive can I upgrade on my own or do I need a Microsoft branded version hmmmmm?