My DH is the kind of guy who is always planning What would he do if....he got attacked by a bear, something came crashing in his windshield while he was driving, etc.
We're foster parents, and right now we have five kids ages 5 & under (two we've adopted

, three are foster). It's been really hard to keep up with daily life, especially since the baby has been really sick (and we moved to the country when the baby was only a month old! yikes). So he's often saying things to me like, "If you were to die, I'd have to use all paper plates and plastic spoons because I wouldn't be able to keep up with the dishes." haha. He worries about how he'd manage the day to day if I were gone, but we haven't really gotten a good handle on organizing our finances. I like to be in charge of the daily/bill paying end of things, and give him the long-term stuff like 401Ks and such. I need to create a better system for ME, let alone someone to take over.
I have done the flylady journal, but have let it slide the last year or two, what with the move and all the little munchkins and their crazy schedules. I need to get it going again, but one page has continued to be useful - the one with all our "numbers" on it, like CC numbers, library card login, etc. I still use that all the time.
I stay at home with all the kids, and a notebook full of routines, medicine info, info about the kids (therapies, medical issues, caseworkers, all that stuff) , etc., would be extremely helpful to DH (or other family members who'd come to help out). Way too much to figure out from scratch, especially in a stressful time.
And not just if I die - like PP said if I'm hospitalized or hurt or something....or if a family emergency came up and I needed to go help or something.