For more than decade I have favored exploring the Moon first,
but I haven't been a fan of NASA building a lunar base.
I think any base building fever should be focused upon Mars.

Perhaps if NASA *has to* have a lunar base, then they should put it at L-1.

I don't think we need a permanent NASA lunar base. I don't think a lunar base is particularly challenging- unless challenging has something to do spending large amounts of money. A Mars base, could be more challenging- in the sense having various technical problems that might be useful for NASA to work out.
In addition if you explore Mars with crew, then you need a permanent base.

Now, I suppose that if NASA wants to put a nuclear reactor on the Moon [largely because a nuclear reactor could been seen as close to a necessity on Mars] then I suppose that would mean NASA should have a lunar base and it would in this way actually serve a purpose as a test bed for later Mars exploration.

But generally speaking I think NASA should in regards to the Moon, be focused upon determining if there is minable water. And I think that the private sector should/could build "bases" on the Moon.