1 - a base that isn't good at keeping the figure up or holding it up.
3 - a base that's likely to break or fail due to poor construction, short pegs, etc.
5 - a plain base that does its job.
7 - a base that does its job and maybe has some decals
10 - sculped base, well executed, as well as doing its job and keeping the figure up.
Honestly, I'm not too fussed by 5 bases (figmas, RAHs) but I prefer bases that would score 7 or higher.