My Thoughts

I think it's definitely worth setting up favicons for as many different devices as possible. You never know who will want to pin or favorite the site on whatever device they have. That extra bit of effort can go a long way, as with many things in development. The problem is the standard for favicons is terrible right now. Between all the different devices, operating systems, browsers, and screen resolutions out there, to support everyone is a huge pain and it pollutes the head of your HTML document with numerous lines of link tags. To be perfect every single time requires lots of research and testing.

I like the concept of an .ico file supporting multiple sizes in a single file, but what I really want is vector support for favicons (like an SVG image). This way I could do it once and know I'm supporting everyone's needs, but that will probably never happen.

Note: It's probably worth saying that favicon images need to be custom tailored in some cases. For example, you may want a different image depending on the size. So even if a vector image was possible, it may not be ideal.

Below you will find my default go-to for setting up favicons. There's a ton of information on the web, and many favicon generators seem to generate different sizes to which they think the standards are. Skip to the bottom of this article if you'd like to check out those resources and references to create your own.