1. sys-admin reorganisation, moving content from one spot to another without redirects in place.
2. developer reorganisation, for example moving from "confusing" urls to "slug" based urls without adding redirects
3. fragile content, content that moves depending on external changes (beta to release for example)
4. product retiring or companies getting acquired
5. hackers messing stuff up in a way that can not be fully repaired (or an non-recoverable data loss)
1. sys-admin reorganisation, moving content from one spot to another without redirects in place.
2. developer reorganisation, for example moving from "confusing" urls to "slug" based urls without adding redirects
3. fragile content, content that moves depending on external changes (beta to release for example)
4. product retiring or companies getting acquired
5. hackers messing stuff up in a way that can not be fully repaired (or an non-recoverable data loss)