There are few things in Anthea's life that are constant.

Her appearance doesn't change (much). She was blonde for awhile, black haired another time, and once - in a misguided adventure - she woke up with dyed pink hair. Some times - when she's feeling particularly bold - she'll change her makeup, or try on a new suit, or wear a different shirt. But she doesn't like to change her appearance too much (national security, and all that).

Her routine doesn't change much either, aside from the occasional war or assassination attempt. She makes tea (or, occasionally, coffee), kidnaps Sherlock's friends, and saves the world. It's really no big deal. Most days are quiet and repetitive, and she likes it that way.

Her boss doesn't change either. Mycroft remains an island in the middle of a troubled sea. Some days, she notices little quirks about him, like that he's unconsciously switched to using his left hand, or that he blinks more than normal. Some days, she thinks the pressure might break him, and so she stays particularly close to him that day, coming up with ridiculous excuses to be close to him. Some days he doesn't notice her, and some days he does. The good days are the ones where he does.

But everything else is subject to change.