Chess rating milestones

I think everyone values certain milestones differently, but I think almost everyone views it in "steps" of 100 point increments after about 1000 rating.

I think 1500 is a big milestone because they seem like a grandmaster to the beginner at chess around 1000 rating. Plus, by 1500: you probably have an adequate knowledge of basic endgames and checkmates already as well as some tactical knowledge and perhaps even starting to dabble into openings.

I think 1800 is a really huge milestone because USCF Class A is really good for the "average club player." Reaching 2000 rating is probably the next big accomplishment because you now have a "2" in front of your 4-digit rating! 2000 rating is already considered "expert" level and is already rare to meet. Even 1500, most chess players never reach statistically-speaking (although that would be only mediocre to many club player levels). 

For the few that ever reach 2000+ rating, 2200 is perhaps one of the hardest "steps" to make because it usually takes a 2000 player about 3 full years of dedicated chess study to make it to 2200 - if they ever make it there at all. Of course, anything after this is always super competitive and elite chess play.

Source: coming from a humble 1800 player and parroting what I've heard from friends who have made it much higher than I have so far

p.s. Rating is always relational. A 2000 rated expert is the loser at a field of grandmasters and a 1000 player is seemingly unbeatable to a 500 rated player. I think the chess.com rating average is around 1000 and USCF average is around 1150 or so, but keep in mind that rating pools are important. In a "local chess club", 1500-1600 is common and many chess clubs have most members between 1000 and 1900 with there almost always being at least one player rated 2000+ in a club. Why is this so skewed? It is because the weaker chess players by rating are less inclined to join chess clubs and seek chess games. Only the dedicated and stronger players seek this, so you are usually going to find stronger chess players than the general public average in a chess club. Even if 1000-1200ish is "average", I would say that 1600 or so if a fair assumption as "average" in most chess clubs where the general talent is greater than the average chess player anywhere.

What about smaller milestones? Like for example. In the past month i went from 200 Elo to 400 Elo. So 300 and 400 Elo were milestones for me. Especially 400 elo. I just got to it about 5 minutes ago. For me small milestones count as 100's improvements. Like if you were 1000 Elo, your next small milestone would be 1100.