Weighing the pros and cons of subclass choice, feature choice, new spell choice, swapping old spell choice, possible multiclassing choice, and rolling or static HP choice all take time.
In my experience this time is cut down considerably if the player has access to a good character builder. Searching multiple books, or even back and forth in the same book has never taken 2 minutes for me or any of the player's in the group I DM for.
Edit: I forgot Feat vs ASI choice, or even ASI versus other ASI choice.