We should have 4 backup jobs
Definitely 4, not 3, and 5 is right out.
Unless of course someone builds a 500GB database with SQL CLR UDTs which slow down DBCC to a crawl, so you move the backups and maintenance for that database into their own jobs or steps with different flags, and possibly start staggering some stuff so it finishes on the weekend without dripping into Monday.
Then you’ve got more. But just kind of sweep them under the carpet. We have file system backup checks so that covers most of it…
These are just administrative test examples; when you have to start testing queries and procedures, it’s a whole new level of fun, as it feels like you’re building a castle on sand.