The way I do it on both Linux and Windows is: all the downloads go into Downloads folder. I keep the folder sorted by date (newest top) - 90% of the time I'm looking for something recently downloaded, and for the remaining 10%, I usually have an estimate in my head how old the file is, so I can do a visual binary search on the dates quickly. When I need to free up some space on the drive, I resort the folder by size (descending), and start deleting from the largest files down.