Define "best" and then define "your product". A library for a programming langugage will have very different idea about versioning than let's say, Microsoft Office.

For public consumption - year.version.

For libraries and even the internal version number of a public product like an OS release where developers still want to say.

if os.version > x:

standard semantic versioning.

I use semantic version for basically everything. Even for non-technical users, it's at least OK. Breaking changes are a pretty easy idea.

Year.version might be better for marketing though.

I developed and shipped one product with monthly releases for decades and always simply bumped the version by one: 1, 2, 3..

Anything fancier doesn't really tell you exactly what features changed when, so a table in the documentation spelled that out for each version.

I have an iOS app and I stick with the usual semantic version scheme. It’s easy for me to use. If I jump to a new major version it’s easy to explain to users.

I like the classic as it provides actionable information.

Although knowing the date is nice, especially to indicate an application is dead end. But I rarely need that. When I first download it, and when I wonder ... hmm is this product ever going to be updated.

I am not sure what the value of putting the year in the version.

For my own home projects, and work pre-release, I always list the build date on the screen. Saved me more than a little frustration.

You could combine them. Either Year.Major.Minor.Patch, or the other way around. But like I said before not sure of the value.

It really depends on your release plans.

If you are actually going to (attempt to) support multiple releases, semantic major.minor.patch is very useful.

If you're really just going to support only the latest, semantic versioning is probably not so helpful, year.version is easy to figure out chronological differences with.

githash as the only version identifier is a sign that you don't intend to help users track versions. This could be the right choice if you want to release something without expectations of use.

Hasn't Ubuntu done year.version for a long time?

I have very little experience this, despite having decades of programming under my belt. The +1 with each master branch merge proved to not be the best as we have seen many programs to switch to year and month type of versioning. Which makes sense as it clearly communicates WHEN the current version was the most up-to-date and it leaves no place for ambiguity.

On the other hand, unlike products, libraries still make sense to version semantically as it is technical information for the users of those libraries that clearly communicates breaking changes.

Since my first app I use semantic versioning, because I think that it makes the most sense for the user.

Depends.

Who’s your user base?