I found 500 to be the hardest target to reach in all my time here.
Now I have never reached 900 at all, more than 2 years after first achieving 800,but I don't think I have ever seriously been closing on 900. I only get to 800+ if I have a lucky sequence of close wins, and have maybe spent 50 games between 800-900 (highest 871), and it always seems a temporary level to me.
But with the 500 target I must have spent 150+ games established in the mid/upper 400s, only 4 at most consecutive wins from the goal, but I could never quite get it done. When I finally made 500 I think it was perhaps another 25 games til I hit 600.
Thanks for sharing your learning curve. It took me 200+ games to get from bronze to silver, and also 200+ to get from silver to gold, but I think about 50 games to get from 400 to 500. I think it has to do with the fact that lotto'ers (~300) and blitzers (~400) get replaced by more cautious players. This reduces the gambling noise from your progress and lets you focus on "real" gameplay.
Also, I am now recording all my games, and afterwards I set myself the task to reconstruct their setups and store the setups as images in a map. I haven't encountered any opponent more than once, so there has been no direct gain from this. However, rewatching the games and trying to reconstruct the setups gives indirect gains. E.g. it made me better understand the logic of my opponents. I find it's a good training that let's me also apply such deduction during the games. As I build up more experience, recognizing setup patterns during the game should become more automatic and cost less mental effort.
I hope to reach platinum in the next 200 games or so. We'll see I am nowhere near a player like Ouwesok who went from 100 to 700 in about 200 games. Maybe I should make another account and see how quickly I can get at my current level from scratch. OTOH, I don't want to face all the horrible bombed stuff, lotto'ers and blitzers again.