I am currently cleaning up my paper files, which lead to the archival and scanning of paper documents of many dead projects. So far, I archived completed ideas, or variant ideas of games I do not own anymore. They will be eventually be released on my Haunted Archives allowing you to notice my twisted mind.
But for video/board game projects, I have problem determining if a project is really dead since any idea could be reused or redesigned into something else. So an idea is never really obsolete. I though of criteria like discarding multiplayer game ideas, but again, multiplayer mechanics could be used in single or two player games.
I scanned my Neopet obelisk war idea due to the copyrighted theme and the multiplayer game, but again, some mechanics are reusable. I will be archiving my master of magic mod attempts for: Warlock, Elemental and Unciv video games. Again, many ideas in those files overlap with the many board games projects I have attempted over the years. So even if I do not wish to mod those games anymore, a lot of content from those files is far from being dead. You could argue that only a small percentage will be usable since it's more specific to the modded game's mechanics.
What are your though?
How do you determine that an uncompleted project is obsolete?
I have assets for completed games and variants. This will be archived.
Most of the stuff to archive or not are design notes, so mostly mechanics.
In a mod for a video game, I could note ideas that are transposable to other games, but I could also have noted a list of perks available in the game that are not always transposable to other games.
The primary objective is to save physical space. On the computer, digital space is not that much annoying. If the project is complete, there is no reason not to archive it.
The main goal is to keep the information accessible in case I would like to dig back without consuming a large amount of space. I try to take digital notes to avoid this scanning process in the future. Or at least reduce it.