Here are my distinctions:
7s are baseline bangable
8s are plate-able
9s have a shot at LTRs
I grow sexually bored of 7s almost immediately and 8s in time. 9s hold the longest sexual sustenance, but even then ...
Also there is no numerical linear attraction. A 7 might not be into my look, and a 9 might. It all falls within types. I do best with Eastern European and Russians.
I agree with
@guru1000 in that there's nothing like banging a hot, porn star-esque 9+ and having heads turn when you walk into a room with her. I've banged and dated plenty of 9's and after many data points have found...
For 95% of them their personalities and behaviors absolutely suck. They're dull and boring and have nothing interesting to say about anything. And they don't have to, they've largely had everything handed to them from a very young age. They're beautiful and it's carried them through life. Rarely do hot women have decent careers and any sort of business or financial acumen. Most aren't that good with kids. MANY 8+'s have serious personality and mental issues--because they have no skills or purpose. So to me, they've gotten to be disposable p*ussy. One, two, three at the most and done. Just my experience.
So, at some point, you need more than hotness to keep my attention. I love hot fudge sundaes, but if I have one every night of the week for 3 months, I'm going to get sick of it.
Right now, I'm pursuing more 7's. I've found they're the best to hang out with and have sex with. Supermodel or porn star? No. But, they're do-able and the ones I date can actually hold a conversation, are intelligent and educated, and don't have "Baby Princess" syndrome or serious mental issues. Had a second date with a pure 7 on Sunday. Took her to an outdoor art show then we had sushi, sake, mead, and popsicles. Walked and talked. She was actually, dare I say, "fun" to talk to. Good vibe and flow. It actually made me want to f*uck her more.
Good luck.