As with the 10th Doctor’s brown suit, perhaps the most noteworthy (non-construction related) observation regarding the blue suit is the various manners in which he wore it over the years.
His wearing styles basically fell into two categories: with a tie (for a more “traditional” suit look) or with multiple layers underneath the jacket and no tie (for a more casual look).
The Doctor tended to go back and forth between the two looks from episode to episode, not really seeming to prefer one or the other but constantly swapping out ties, shirts, and undershirts.
He did tend to wear ties a bit more often than layers with the blue suit, though, as you’ll see over the next few pages.
Numerous people in the costuming/cosplaying community have done fantastic work identifying and documenting the various ties the 10th Doctor wore over the years –even managing to find some of the original ties and/or shirts in the same brand/style used in the show. This information has become readily-available on blogs and social media.
My focus with this portion of the analysis is more about the actual wearing styles than the shirts/ties themselves, and there’s no need to rehash others’ tie research.
Suffice it to say that the Doctor wore several different shirts and ties with his blue suit, although they were nearly always consistent with the previously-established blue/brown color scheme (although the blue suit did expand the palette to include reds).
The brown suit + tie was arguably the 10th Doctor’s most iconic look, and he often wore his blue suit with a tie as well:
Observe that the color palette expanded into the reds with some of his ties – most notably in “Smith and Jones” and “The Poison Sky” (upper left and lower left, respectively).
As a side note regarding this wearing style, if you look carefully, you will see that whenever the Doctor wore a tie with his suit, he always wore his ties slightly loosened, with his shirt’s top unbuttoned.
Just as the Doctor occasionally wore his brown suit with no tie but with various layers underneath, so he did with his blue suit:
One notable deviation from the usual “layered look” was that Tennant occasionally wore the undershirt’s collar over the suit jacket’s collar.
An amusing quirk of Ten’s dressing style was that he wore his suit jacket’s buttons differently each episode; he would always change which buttons were closed and which ones weren’t (probably driving the costuming and continuity departments crazy).