If any of my previous jobs prepared me for family research, there were three.
1. Medical records clerk. Taught me to read diagnoses. I actually attended a community college to become a Medical Librarian. It got kind of boring, I ran out of money and found my next job, which was number 2.
2. Medical transcriptionist/pathology secretary. This has probably been one of the most useful occupations in preparing me to read old records. I read doctors' handwriting for a living. I read and transcribed pathology reports and autopsies and had to call doctors' offices with results of laboratory tests. It gave me a boost when looking at old records.
3. Library clerk. This was useful in a different way. I was fortunate to live in a city with a population of 100,000 that operates four libraries and that was a participant in the interlibrary loan system. If I found a branch of the family was mentioned in a book that was available somewhere, I requested an interloan. You didn't have to be a library employee to interloan, but it sure helped when you had a weird request and the branch librarian would manage to get it through the system. (Gee, I miss you TLP.) I know one of my cousins/friends is really grateful for this too!