Maintenance of an ASPNet MVC project. How does this happen?

Question

ASP.NET

Good afternoon. Interested in the following situation. For example, I made a website using ASP.NET. Everything suits, after a couple of months I wanted to fix the design a little, add a couple of functions. And how to be? Stop the entire site, rebuild the project and upload again? Add "handles" for scrolling immediately to the site like WordPress. Or there are some less stringent measures to add functionality or edit the site design.
And what are the current best practices when building a website using C#? Is this decoupling the backend from the front?

Answer 1

All projects are different. The main point is to do everything so as not to break what works while improving. There is no silver bullet. In general, for the project, as well as for the class, the SOLID principle is our helmsman.