1. To sue someone for statutory damages and to have a good chance of automatically recovering attorneys' fees (which helps make the legal effort worthwhile rather than a Pyrrhic victory), when you don't have a clear argument for actual damages, you need to have registered copyright of the work, at least in the US and probably most other countries with statutory damages.
2. If you just want to be able to issue takedowns or sue to get someone to stop redistributing something you made, and maybe if you have a clear argument for actual damages and don't need to rely on statutory damages (which are usually absurd anyway), you don't necessarily need any copyright notice, much less copyright registration, since, due to the Berne convention, everything is assumed copyrighted.
However...
I think putting a copyright notice including a year in static documents is good practice, though, for a simple reason: Copyrights expire. In order to know when the copyright expires, someone who encounters your work needs to know when it was created, i.e. when the copyright period began.
To remove any indication of the initial year of creation is essentially to admit that it doesn't matter because copyright terms are so absurdly long that you don't anticipate anyone caring about your stuff by the time copyright expires.
As a corollary, don't update the copyright year unless you make non-trivial changes to the code, text, or design. Is it really worth it, in some hypothetical distant future where your work is still economically valuable, for you, your descendants, or estate, to go after someone using a slightly modified later version of the work that isn't technically out of copyright but the original version is?