Document repositories such as SharePoint accumulate clutter overtime and this impacts the time it may take to retrieve what you are looking for. Knowing what you should be filing is the first step to remedy this: don't file what you don't need!
As a first step, be sure to know whether "Your Recorded Information is a Record". If it is, then you should be storing it in a location that will be accessible by your colleagues. Be sure to name your file well to help you find it quicker later!
Click here to download a PDF guide, "What Should I File in SharePoint"