I do the main quest just for the shouts.
I get up to completing the Horn of Jurgen Windcaller, learn DAH, and then go out and do my own thing.
Then when everything else is done, I finally follow Delphine down to her private area in the inn.
>"Follow me, we can talk in private."
>Exit inn
>Complete DB questline
>Complete Thieves questline
>Complete College questline
>Complete Companions questline
>Complete Daedric quests
6 in-game months later...
>Return to the inn
>Delphine acts like I haven't been gone for half a year