Hmmm good question.

The best answer is - do consulting when you're single & young, or older and an empty nester.

It's hard to make consulting work when you've got young ones at home to raise, hard on you, the kids, and the spouse.

I worked with consultants who left their country (India) to work here in the US. They left their wives / kids behind for months / years at a time.

I could never understand that because if it was me I wouldn't do it.