- sub $10M: focused on making the money last,
- $10-$50, you are rich, and you are concerned about passing some money to your kids,
- $50MM + up until 9 figures: keep it for generations,
- $1B plus: all about charity.
While there is certainly some wiggle room I'd argue the thresholds are much lower:
<$5M - enough to never work again, can buy anything but not everything
<$25M - enough to buy anything and everything. You'll never spend this down so you need estate planning, child management -- there is a reason banks target this level (and even $10M in some cases) for their absolute best services, because they know it too.
<$100M - here's where you get into "estate planning" type activities (tax, trust) on a daily basis vs once (at death)
$100M+ - I don't believe there is any meaningful distinction from here on up; there is nothing you can't buy or control at this level that $1B would allow. At this level you have massive complexity; I'd guess you have your hand in multiple businesses and not just in the stock market (I know I would if just for something to do with my time -- I'd wager someone with $100M wouldn't be ok taking orders from others during their "day job").
What I think is interesting as a boglehead is that, if you don't change your lifestyle and investing habits, and you get to the top of category 1 before you retire (which is not a small number of people on this board), you're very likely to get into one or two more brackets within your lifetime even if you never work again because $5M will continue to get significant capital appreciation and you've probably got another 20 years of life ahead of you, minimum.
Personally, I spend a healthy amount of time planning what my wealth looks like next year, in 5 years and in 20 years, and think about the concerns I'll have in the other brackets and have started planning for them now.
You can do anything you want in life. The rub is that there are consequences.