What very old/unmaintained software do you still use today, and why?
I still use Font Renamer to manage my font collection. It works great but hasn't received an update since 2008. Even the website looks straight out of the Windows XP era.
My dad insisted on using CARDFILE.EXE from Windows 3.1 up until he switched to a MacBook in 2010 or so. I still have the data file somewhere.
Gotta admit tho, it was one of the most useful applications that came with a PC back in the late 80s/early 90s. My folks put everything into that thing. They probably had about 350 cards!
I have an old cardfile file I created during University for all my contacts. I've lost touch with almost everyone I hung around then but it's nice to keep it for the memories.