For some reason, I've overlooked using the Social Security Death Interactive Index in my genealogy searches. This free database has already yielded me several pieces of information in the last few days, as well as given me clues for further research and provided some conflicting information that needs to be further researched.
Example of data conflict: John Leland LEMASTER - the SSDI shows his date of birth as April 25, 1902, while other sources show April 30, 1902. Record at FindAGrave website shows his birth as April 23, 1902. However, there is not a photo of the tombstone to verify. Will need to search the actual birth records in Jay County, Indiana to straighten this one out.
The best part about this database, besides being free, is that you can quickly search for information on the scattered lines and find death dates and locations of last known residence, which may provide further clues of sources to research. You can also request a copy of the individuals' original Social Security application (SS-5). This is something that I intend to do for my direct line ancestors, just to see what other details it may reveal.
Not every one is listed in this index, which roughly starts around 1962. Some of these reasons could be: if the death was not reported to the Social Security Administration, if the death occurred before the master index was being kept in a computer database, the person did not participate in the Social Security program, or survivor benefits could still be being paid to a spouse or dependents. Remember, the self-employed, farmers, military personnel, government employees and some professional groups (doctors, lawyers) did not receive coverage until the 1950s and 1960s, so they may not be listed in the index.
I intend to set a reminder to periodically search this database to locate SSNs of those recently added to the database. You never know what you may find out or when having that SSN may come in handy as a cross-reference.