I keep a place for everything, and everything in its place. My download folder is cleaned regularly, usually right when I download the file I move it to it’s appropriate place. Sometimes it still fills up with old installers or what have you, if it is a hard to get installer like for old devices, old games, or niche hardware I store it in a safe place on my encrypted cloud, otherwise if it is new software or frequently updated I just delete it after I’m done.