Searching for a file in El Capitan has gotten a lot easier by using the Natural Language feature in Spotlight. Searching for things like ”Emails from Amazon last month” will bring up all of your order confirmations for items that you bought recently for a quick review.
You can be specific with spotlight and ask it to show you document types such as "Presentations I worked on in December” for any keynote projects.
Can't remember when you created a document? No problem. Simply search for something like “PDFs containing budget" to find documents for specific phrases. -- John R. Carter Sr.