I'm an outlier. I generally wanted to be at the point where I had nothing more to learn before taking the next step. I did take advanced a year after my OW and rescue that same year, but then I took rescue again many years later before taking my DM. I think I had about 1000 dives when I took DM. Part of the reason I waited so long was because early on I didn't have the connections to start working as a DM after I had the certification but a large part of the reason was because I felt for myself, this is the level of experience I needed in order to feel comfortable in the role.
After taking DM I worked as a DM assisting in large part with the OW course and a lot of intros for years while I started taking technical specialties. Again I built up experience as a technical diver kind of slowly. At one point the joke at the club was that I had more experience as a diver than all of the instructors combined. At the time I was one of the few people working there who was technically certified. In fact, I worked so long as a DM that one of my technical instructors was a former student. At that point I started feeling like I was standing still.
Eventually I decided to become an instructor and I did this for two reasons. First and foremost because the shop offered to pay for it, which was incredible generous and there was no way I could say no to that. The other reason was that in the time I worked as a DM I had started to build a real vision of how the OW course should be given and it was different than how I saw my colleagues doing it. However, I needed to have my hands on the wheel if I wanted to see my vision become a reality so this was the final motivation. I do now actually give OW how I think it should be done but as you can imagine in my case, it took a lot of iterations and experimentation to refine the way I do things to the point where I was happy with it.
Obviously there are still things about diving I wouldn't feel comfortable doing. For example, even though I'm an avid wreck diver and I have an ice diving certification diving in a cave, besides seeming somewhat pointless to me, is something that I don't think I'll ever get around to doing. I've been in a few (dry) caves and in one case on an extended tour of 6 hours in a cave system (again dry) with all kinds restrictions and such and even though I found it "cool", I just don't think that squeezing my butt through a little hole on scuba is something I would get much joy from. I'd rather spend that time and the money involved in travelling to interesting far away places in the tropics, but I digress.
Aside from travel, I don't really have any goals for diving per se but the last couple of years I've been taking some courses to be the "student" again. This just re-energizes me and keeps me from becoming too paradigm trapped to be an effective instructor. I guess you can see it as "sharpening the saw".
I suspect that my experience is not typical. There must be other slow-poke learners around but I guess that most divers progress a lot faster than I did.
R..