There have historically been two guarantees in life:
1) Death
2) Taxes
More explicitly from Benjamin Franklin, who apparently stole it from Daniel Defoe (but that conclusion is based on zero confirmation web search, I just went with what I first found because I’m lazy)
“‘In this world nothing can be said to be certain, except death and taxes.”
I would like to add another. If you have a rug cleaned, the very same evening you reinstall it in your living room, one of these two animals is going to puke on it.
Also it helps if you feed one of them bacon grease the night before despite the objections of your wife.
And He Says 
A corollary to this rule is that anytime you bring a new piece of upholstered furniture into your home, one of your kids will get a nosebleed while sitting on it. Within 24 hours, guaranteed.
That’s why my kids stay in the shed out back.