Tonyblack said:
There was that thing with Romana as well, if I remember correctly. She was a Time Lord/Lady who regenerated. But before she decided on her final 'look', she tried several different bodies - rather like she was trying costumes on. She didn't seem bothered that she might be using up regenerations.
My theory was that she hadn't fully regenerated, she was merely in an intermediate stage when she tried out those bodies, so she didn't use up her regenerations.
Of course, another theory was posited by a short story, where an avatar of the TARDIS actually did that whole sequence, and explored Skaro with the Doctor during the events of
Destiny of the Daleks, because the TARDIS was jealous of Romana.