It is best to visually inspect the monument/headstone three times a year. You can use dates that will help you remember such as: the repass date, holiday, birthday or any other special occasion.
In most cemeteries, it is the responsibility of the family to clean and maintain their loved one's stone. Make sure you know the rules in your specific location.
The main causes of leaning are improper footings or backfilling around the plot.
All gravesites in the State of Virginia must be properly marked with the name, location and date of death. This is done by either the cemetery or the funeral home.
Visit https://www.cem.va.gov for all information regarding veterans burials and benefits.