I've never particularly liked or understood the reason for using different lead-ins for women based on their marital status. It seemed to be very old fashioned to me, even when I was fairly young. In my previous life as a journalist, I interned a semester at a newspaper in London. Their practice there was to use honorifics on the second reference to a person in a news article; so if John Doe is mentioned once, on the second time, he'd be Mr. Doe. I always hated having to ask women interviewees whether they were married or not just to figure out what honorific they'd use, so I ended up defaulting to using Ms. a lot of the time. In retrospect, I could probably have just asked "What's your preferred title, Miss, Mrs, or Ms?" but I was 21 and awkward and sometimes the simplest solutions don't occur to you until 8 years later when you're in a completely different career.
So honestly, because of my own personal dislike for the practice, I'm unlikely to start using Mrs after getting married. However, it's almost certain that at least some people will call me that anyway, whether or not I change my name. People have a nasty habit of assuming such things. I've gotten called "Mrs" on several occasions just in my regular life; once even when a boyfriend and I went to a very fancy restaurant when I was only 18! I got it most recently at a doctor's office. This makes me believe that a considerable number of people don't actually know the difference between the different titles and particularly don't understand its historical context.
"In the middle of the eighteenth century, 'Mrs' did not describe a married woman: it described a woman who governed subjects (i.e., employees or servants or apprentices) or a woman who was skilled or who taught. It described a social, rather than a marital status.
Mistress is also the basis of another 'title of politeness' (as the OED terms it): 'Miss', which we use to designate an unmarried woman. Miss is almost as old as Mrs as an abbreviation of mistress and, like Mrs, it was applied only to those of higher social status. Unlike Mrs, which has changed from a social to a marital meaning over time, Miss always designated the marital status of being unmarried. But until the eighteenth century it was only applied to girls, never to adult women." - Mistresses and marriage: or, a short history of the Mrs, by Cambridge University historian Dr Amy Erickson. (This paper is really fascinating - Dr Erickson looked at a ton of old records to see what titles were being used over time)
The use of Mrs for women in authority can also be seen in the use of Mrs for "Mrs Hughes," the housekeeper in charge of all the servants on Downton Abbey, taking place around the time of the first World War. Dr Erickson also notes that the appropriate title for single business women in the 19th century was also Mrs.
Quick sidenote: I've been reading some Jane Austen lately, and this paper also describes the naming conventions used there.
"Where Miss was used, it followed the conventions of Mr for sons. Where the father was 'Mr Cibber', his sons were 'young Mr Cibber' or 'Mr Theophilus'. With daughters, the eldest unmarried daughter was 'Miss Cibber' with no first name, the younger daughter was 'Miss Charlotte Cibber', or just 'Miss Charlotte'. When she married she became Mrs Charke, or Mrs Charlotte Charke to distinguish her from any other contemporaries who were also Mrs Charkes, notably her mother-in-law"
Surprisingly, the "tradition" of calling a wife Mrs. "Husband's First Name Husband's Last Name" is actually fairly new. Dr Erickson's paper continues snarkily, "Through the early modern period, where Mrs was used and the woman was married, the title was followed by her own first name and her husband's last name. The total annihilation of wifely identity which assigned a woman not only her husband's last name but also his first name only appeared around 1800."
Here's the thing: Is it actually appropriate for someone to call a married woman who hasn't changed her last name Mrs? According to several sources, such as Miss Manners and Offbeat Bride, no, as Mrs in this instance literally means "wife of" and actually only makes total sense when used with the husband's complete name.
So since I don't plan to legally change, it sounds like I will not be partaking of any of the fabulous and often glittery "Mrs." themed garb out there. Oh well. There's still plenty of other ways for me to engage in blatant wedding themed consumerism.
Sidenote: I really wish I could find some fabulous MS. NOT MRS. merchandise out there. When I searched for "Ms. T-shirt" I just found a ton of stuff for Multiple Sclerosis.
Anyway, I'll leave you on this note: