What is taxable income?

[retire@40]

...now you know why I think it is such a dandy idea to self-incorporate, (LLC, Sole Proprietorship, S-Corp, whatever) in ER if you have any intention to do part-time work.

I agree that doing some part-time self-employed "work" is a great idea. You can do something you enjoy, be able to write off some expenses, and hopefully end up with just enough profit to max out your Roth IRAs each year.

I know a painter that loves to travel the world in search of that perfect landscape to paint and is able to earn enough to pay for his trips that are tax deductible, write off all the paint supplies, and sell his paintings to earn enough to make a profit to fund his retirement account.
He laughs when people think he's "working."

It's dangerous for a type A workaholic to go back to work in any way IMHO. I still get the urge but have resisted so far. I just can't do anything halfway it seems. It's always "Damn the torpedoes, full speed
ahead!" Better I should just keep loafing I think.

JG