I buy and sell faction/deadspace/officer mods, ships, skill-books and implants with traders covering all 5 major trade hubs (Jita, Amarr, Dodixie, Hek and Rens) plus secondary hubs in most other empire regions. I have 23 active traders, 3 on Jita (one each for mods, implants and skillbooks), 20 more with each covering a different region and a few more in training.
In December my net worth is up 22 billion after expenses. I also sunk another 12 billion into getting all my accounts subscribed 2-3 months in advance (into late Feb or March). Taking that into consideration I actually made 34 billion this month.
Continuing my trend of the last several months, I didn't spend as much time working the market as I used to. I have things down to the point now where I seem to be able to reliably make 30 billion a month with minimal effort (20-30 hours a month posting / updating orders). That's 1 - 1.5 billion per hour and seems to be my sweet spot for optimal ISK/hour.
I find spending more time working the market has diminishing returns, the more hours I spend at it, the less I make per hour. It's often better to just post things at a good price and leave them up until they sell even if it takes a while. I make a bit less but it's a lot less work and I can use the time I do spend on more profitable investments.
I have enough ISK now that I can afford to be patient and work longer term trends. I really don't need quick sales turnarounds and capital reinvestment to keep my income up anymore so I can let a lot of ISK sit idle in buy and sell orders for days or even weeks while waiting for prices to improve.
Current net worth is 382 billion with about half in cash and market escrow. Most of the rest is in sell orders and recently acquired stock I haven't gotten around to posting for sale yet. Very little is in assets I don't intend to sell soon, mostly ships and mods I keep in stock for my own use, maybe 4 billion worth and very recently a small stockpile of PLEX worth 5-10 billion.
That's my actual current total net worth, I don't pad the numbers by counting ISK I've earned but have since spent and no longer have. That'd be like calling myself a real life millionaire because I've earned over a million dollars during my life when the reality is I've never had anywhere near a million dollars in total.