"Clothes," as the Doctor patiently explained to Jo (not for the first time), "make the man." Not that the Time Lord didn't have a vast array of fashionable suits hanging in closets throughout the TARDIS, some in areas he'd probably forgotten about by now (and of course after having thoroughly torched the wardrobe of his predecessor, no offense to the bowl-cut headed chap). But sometimes a chap just had to get something... new. New being a relative term for someone who had the ability to travel in time as well as in space. What was new in one century becoming automatically old in another. But as his clothes aged no more than he did, following the natural (or unnatural, depending upon one's viewpoint) laws of the universe, he was able to shop for a fresh set of glad-rags in any time which he chose to visit. Or happened to end up in.
The Doctor was a man of very refined taste, as he was wont to remind Miss Grant. And not just anything would do. He'd seen some grievous sartorial errors in his day. In fact, he had fought hard against the ruff when it had first been introduced. Damn ridiculous thing that was. On the other hand, a kilt was a very fine thing indeed. Very masculine. And very practical in situations where one needed the complete and unfettered use of ones legs.
Which was his reasoning behind taking a little jaunt for the sake of fashion to Scotland. He had aimed more or less at Edinburgh, circa somewhere amidst the early 1960's or so. Had to be careful with that. A bit of a mis-step and she might end up in London during the Blitz and that wouldn't do at all. Not that he would admit to having less than full control over his vessel, mind you.
When the TARDIS had finished materializing - hopefully not in the middle of downtown Glasgow during rush hour - he waved the still protesting Jo toward the door. "It'll be fun," he promised her. "They make them for ladies too, you know." Although the prospect of his and her kilts wasn't exactly the image he was striving for.