I think I might have enough data in Quicken to cobble something like this together, so I'm going to go back and take a look.
I've been at this for a while (I'm 50), and my record-keeping was not as good in the early days (for instance, I didn't track my 401(k) in Quicken), but here's what I was able to pull together.
I graduated from a master's program in 1998 at age 31 with a NW of $0. (No student loans, but no assets other than a beater car, a bunch of books, and a bad case of eye strain.) I spent a long time as a perpetual student for many reasons--I never really knew what I wanted to do with my life so I kept temporizing. I made it to ABD in one discipline, decided not to finish (long story), and then did a master's in a different field. Both programs were decidedly unmarketable. So while I had no student loans, it's pretty much the same as if I'd financed a four-year degree and took 10 or so years to pay it off.
Oh, well--hindsight is 20/20, and there were all kinds of personal and psychological issues which led me to take this path. Thank God I was naturally frugal, born with the saver's gene, and had some good role models for frugality and financial responsibility in my friend base--otherwise things would have been very different.
On reflection, this was in a time long before anything like the FI/RE movement was anything close to where it is now--the resources and mindset were just not "out there" in the way that they are now. The closest thing I can think of is the Dave Ramsey thing--the idea of reaching "freedom" from debt, but not "freedom" from working-for-money. Even now it's a sub-culture for weirdos--a term I use with affection and fully including myself. :) That's a topic for a different day, though.
So we'll start the clock in 1998, I guess, which is the first year I finally logged a 5-figure salary ($12K). ;-)
NET WORTH PROGRESS
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$0 - $100K: approximately 6 years (2004)
$100K - $250K: approximately 5 years (2009)
$250K - $500K: approximately 4 years (2013)
$500K - $750K: approximately 2 years (2015)
$750K - $1M: approximately 2 years (2017)
I feel kind of wimpy next to what all the "kids" (i.e., anyone 15 or more years younger than me!) are doing today, but I can still look back on it with a degree of pride--I did what I could with what I knew, and was always seeking to learn more. I guess it says something about my savings rate to note that I reached $250K in 2009, since we know what was going on THEN! ;-)
My two regrets are not learning more about investing earlier, and not marrying my then-best-friend-now-husband 5 years earlier. ;-)