Time. With a wife and three kids and of course a business, that takes up a majority of my week. I remember in my 30's wishing I had the money I could do X, X and X. Life is just weird that way, it's always something. My plumbing business has never been better. My wife is now a top executive. We are debt free and both 47. We worked our azz off,a been to hell and back and solved that issue but now we have time issues. We are out of time. 3 kids take a lot of time, we spend lots of time with the kids and we love it, I'd have it no other way. So we seem to be on that stage and I suspect the next stage for us once the kids are old enough will be "health" issues. Lots of people 10-15 years older than us seem to battle health issues. It's crazy. I love building anything airplane related but it's just a hobby. I love my time with my wife and kids, I wouldn't trade that for nothing. I have a project I'm pecking away at and this time I've been very quiet about it. I get to the shop about 2-3 hours a week at most. That makes for a very looooong build but I'm ok with it.