So most of the time, I can see that people divide OTH in two different ways :
- seasons 1-4 / seasons 5-9 : so school years / adult years.
- seasons 1-6 / seasons 7-9 : so core 5 / after leyton left.

I feel like both can fit. I mean, I love the show more during the high school years and after it's a different area, atmosphere (which I adore too). But on the other hand, you have this other cut I kinda agree with. I feel like the show was completely different after season 6 meaning after Leyton left. Season 9 was awesome and season 7 good but season 8 (except for some episodes) wasn't as good as the rest of the show. It's quite normal since two of the main characters left and that a bunch of new characters arrived.

both fit ;)

but i divide it in three :p
1-4 // teenage years
5-6 // adult years with all the main characters (but yeah that can fit into the 1-4 too and go like 1-6)
7-9 // still adult years but not quie the same with when all the mains were there

^agree with that one too :)

For me its simple:
Season 1-6 OTH
Season 7-9 OTH 2.0

After Leyton left it was like watching another show. They re-written history and change the story in unimaginable ways. Obvious to say, the first part was the best.

agree svety74

For me definitely!
I missed LP but for me the show changed so much after s4 to s5 more than it changed after s6 to s7!