Previously, Advanced Find included the clause ‘Older than X Months’.
However, with the new enhancement in CRM 2015, your searches can be more versatile. Now, the clause ‘Older than X …’ includes options for Minutes, Days, Weeks, and Years, which allow you to retrieve search results that are targeted and relevant.
There are many instances where these new clauses can be used, especially when you are needing to look for Service Cases, Marketing Campaigns, and Activities in a specific time frame.
Hope this helps.