I hang on to almost all my installer files, they are stored in a folder on a separate partition, and sorted into subfolders, such as "antimalware", "PC maintenance tools", "multimedia" "MS packages" etc.
This will facilitate a re-install.
(You don't want to be swanning around the 'net, looking for an AV to download, on a brand new OS.)
Tell the truth, I've got rather too many, and some of them are seriously out of date. And some I'll probably never use.Heck, some I don't even remember why I downloaded. The more you keep, the more ongoing maintenance is required to look after them.
Must have a clean up, sometime.