I've been playing D&D 5E for a few sessions now, and I was wondering if a character can select two (or more) different sub-classes by multi-classing in it's own class.
If so, do I have to "re-pick" level 1, 2 and 3 (at the cost of level 4, 5 and 6 XP) in this class before being able to choose an other subclass? I assume this would be highly inefficient and XP-consuming to have twice the level 1 and 2 bonuses since they wouldn't stack. Or can I just double pick level 3 and then the new archetype?
For example, is it possible have a level 10 way of the open hand and drunken master monk ? (Yes, I'm aware this example might be pointless)