As many others I have a folder for all my ripped CD-releases and official releases, but I also has folders for single tracks from no specific album, just single tracks. In these track I fill out "Artist" ,but should I fill out "Album Artist" also? even if it is just a single track with no album or release attached to it.
It depends on your needs. If your player want such an "Album Artist" to sort your tracks correctly, you should fill it. If you never want to sort your tracks to a complete album and play them from first to the last track you could leave the "Album Artist" empty. If you own compilation albums like "Top 40" or "Best of Rock" you have to fill the "Album Artist" for sure. For the last case,
Various Artists is a common Album Artist name.
I think that this is much more a question about how your player copes with missing data.
If you have files with data in the fields ALBUM and ALBUMARTIST how does the player treat files with no data in these fields? Does it group them all together so that they look like they belong to the same album? Or does your player then refuse to consider any data from tags at all and uses only the filename?
as soon as you know that you know which fields you have to fill.