I like the below format:
YEAR, MONTH, the the DAY.
When SORTING via the computer, say pictures (or other documents) it sorts by YEAR, MONTH, the the DAY.
For pics using the YEAR, MONTH, the the DAY format gives you the pics in a chronological format. You get pics listed in the order they happened.
Fast forward 14-15 years
For documents, ditto
For warranty papers ditto.
Most important thing is the YEAR, followed by the MONTH, least important thing is the day.