Another area which causes all sorts of confusion is figuring out a married woman's maiden name and making assumptions based on her tombstone, and her name in her husband's will and other legal documents.
Today, we're used to women (if they take their husband's surname) going by their given name, maiden name, then husband's surname. Example: Ruth Murray Jones married Samuel Smith. After marriage, she uses Ruth Jones Smith.
The problem is that this naming practice didn't really exist until the middle / end of the 19th century. I have seen a couple of instances where a woman did this in the 18th century, but it was extremely rare.
In the 19th century, and earlier, using the names above, after her marriage, Ruth would be known as Ruth Murray Smith, and what a lot of researchers do is apply 20th century naming conventions and assume that Ruth's maiden name was MURRAY.
Don't just take my word for it. Here are some examples.
John HUDSON & Ann Young MASON
10 Mar 1825, Putnam Co., Georgia - John Hudson and A. Y. Mason married in Putnam Co., GA. I've not seen the original paperwork of this marriage, but an abstract of the marriage record gives the name as Ann Y. Mason.
2 Aug 1856, Putnam Co., Georgia - John Hudson writes his will and leaves a bequest to his wife, Ann Young Hudson.
It's always possible, until further proof is found, that Ann was married previously and that "Mason" was the surname of a prior husband. I've not found parents for Ann and I've not seen the original of the marriage record to know if it identifies Ann as "Miss Ann Y. Mason" or "Mrs. Ann Y. Mason." But it is safe to assume that "Young" was Ann's middle name and not her maiden name.
John SMITH & Elizabeth Hawkins UNKNOWN
16 Oct 1747, Amelia Co., Virginia - "Elizabeth Hawkins," wife of John Smith, relinquished her dower in land her husband sold to Thomas Watkins.
9 Aug 1787, Franklin Co., North Carolina - John Smith wrote his will and named his wife, "Elizabeth Hawkins Smith" one of the executors.
I've seen a whole bunch of trees which give Elizabeth's maiden name as "Hawkins" and this may be one of the rare instances where that is correct, but I hate to make that assumption.
Hannah Hawkins SMITH & James LOCKHART
8 Jan 1770, Warren Co., North Carolina - James Lockhart and "Hannah Hawkins Lockhart, his wife" sold land to Thomas Turpin.
9 Aug 1787, Franklin Co., North Carolina - John Smith (the same person as above) wrote his will and named his daughter, "Hannah Hawkins Lockhart."
2 Oct 1798, Johnston Co., North Carolina - James Lockhart wrote his will and named his wife, "Hannah Hawkins Lockhart."
I've seen a lot of trees giving Hannah's maiden name as "Hawkins," which isn't correct.
And, finally, James JACKSON & Ada Jane MITCHELL, which is the earliest I've seen in Georgia of a woman making her maiden name part of her married name.
Ada went by "Ada Mitchell Jackson" from the time of her marriage, and this was such a singular event that her husband noted it in his obituary for his wife.
The Southern Christian Advocate, 28 Feb 1868: An obituary, written by her husband was published in the Southern Christian Advocate - "Ada Jane Mitchell, my wife -- dropping after our marriage the Jane, and calling herself Ada Mitchell Jackson..." Source: Death and Obituary Notices from The Southern Christian Advocate, 1867-1878, database online at Ancestry.com.