To keep an eye on the age of your site stock simply drag Days in Stock (abbreviated as DIS) from the Column Chooser. You can then sort ascending or descending.
Generally, we calculate the DIS from the consignment date on new, or from the date that you manually added to your DMS in the case of used stock.
For a used stock list you could also consider dragging in the 'Stand in value' column in the same manner.
Save this view for quick easy reference another day.