> If you add a new thing (constant, route, feature flag, property, DB table) and it immediately needs to be added in 4 different places (4 seems to be the standard in my current project) before you can use it, that's not DRY.
The tricky part is that sometimes "a new thing" is really "four new things" disguised as one. A database table is a great example because it's a failure mode I've seen many times. A developer has to do it once and they have to add what they perceive as the same thing four times: the database table itself, the internal DB->code translation e.g. ORM mapping, the API definition, and maybe a CRUD UI widget. The developer thinks, "oh, this isn't DRY" and looks to tools like Alembic and PostGREST or Postgraphile to handle this end-to-end; now you only need to write to one place when adding a database table, great!
It works great at first, then more complex requirements come down: the database gets some virtual generated columns which shouldn't be exposed in code, the API shouldn't return certain fields, the UI needs to work off denormalized views. Suddenly what appeared to be the same thing four times is now four different things, except there's a framework in place which treats these four things as one, and the challenge is now decoupling them.
Thankfully most good modern frameworks have escape valves for when your requirements get more complicated, but a lot of older ones[0] really locked you in and it became a nightmare to deal with.
[0] really old versions of Entity Framework being the best/worst example.