My character is a level 29 in the basic game. I've heard about two expansion packs that have been released. Is there any logic as to when you play the expansions? Should I wait until I've finished the basic game or should I add them now?
Thanks.

I started Dragonborn on level 35, and it has seemed pretty easy( adept ) most of the way. Very very fun, but easy. I'd say at level 29 you should be ready for it.

Either pack can be played at any time (well DG is designed for you to start it at level 10)

Hearthfire can be played right away, although you won't have any money to buy the construction materials right out of Helgen.

If you are a heavy RP'er (like myself and many others), it may be best to start each expansion "when your character is ready". Meaning that whenever your character hits a certain stage in their development, according to how you've designed you character's template/personality.