Last week I bought a new sweater from Eddie Bauer. When I went to put it in my closet, I found I already owned the same sweater.
Every once in awhile I'll go to buy a book on Amazon and it's super software will remind me of the exact date that I previously purchased it.
Similarly, if you're looking for an idea or a solution to a problem, you tend to look for the new thing to buy.
In reality, someone already had the idea you're looking for, and somewhere a record of it likely exists: in a blog post, an article, a book, or a colleague's memory.
It's tempting to always go buy the shiny new thing, but there is a cost in doing so, one that can often be avoided if we just take the time to look at the sources already in our midst.