I still address envelopes Mr. & Mrs. Husband’sFirstName Husband’sLastName. It will often appear that way in the phone book, too - which I still use occasionally for work. In spoken address I will use Mr. & Mrs. Husband’sLastName, even if the missus kept her maiden name or did a hyphen thing.
If I know the woman is married but am writing her I’ll use Mrs. First Last (missus). If I don’t know whether she is married I use Ms. First Last (miss). For a girl I’ll write out Miss. In spoken address I use Missus Lastname or Miss Lastname depending on personal knowledge of her marital status.
I learned these forms in… kindergarten and first grade, I believe. This century.
~Max