Ever have one of those clients that just couldn't remember when she worked for her employers?
Here's an idea:
Have her go to the local social security office and get dates of employment by using her social security number.
The listing is somewhat hard to figure out, but it does list all the employers and dates of employment as well as wages/salary paid to that person.
The document is confidential -- that's why your client has to go in person to request it.
Thanks to Camille Carboneau for this tip!