There is a certain kind of household knowledge that lives entirely in one person’s head: which drawer has the insurance papers, which bill is annual, which key opens the small box, which email account gets the statements. It works until that person is unavailable.
Notice the invisible knowledge
Walk through an ordinary week and pay attention to the things only you seem to know. Those are often the most useful details to document because nobody realizes they are missing until they need them.
Keep the system plain enough that you will actually open it again. A clear note written today is more helpful than an elaborate setup that becomes too intimidating to maintain.
Create a one-page map first
Before building a big binder, make a simple index: category, location, contact and last review date. That page can point to a safe, a digital folder, a professional office or another secure location.
Think less about how tidy the system looks and more about how it would feel to use under pressure. One clear label can be kinder than a beautifully organized box nobody knows how to navigate.
Use labels another person would understand
Your shorthand may make perfect sense to you. It may not make sense to your sister, adult child or executor six months later. Plain labels beat clever codes for everyday organization.
You already have enough structure unless another page or layer would genuinely help you reduce the number of places someone has to check.
Do not mix security with convenience
A treasure map is only useful if it is where somebody will find it. Keep the completed record in one known place, and make sure the right person knows which place that is.
If a section feels emotionally heavy, separate the practical decision from the personal one. You can record the contact or location today and come back to the wording of wishes or messages another time.
Test the system with one trusted person
You do not have to hand over every detail. Ask a trusted person whether they could locate the key categories from your index. Their questions will show you where your system still depends on your memory.
If the system starts feeling heavy, check for these two habits: organizing by a private logic only you understand; keeping five conflicting versions of the same information. They can look organized at first, but they usually create more work.
The best test is simple: could someone find the right place without calling you? If yes, your map is working.
The part worth carrying with you
General information, not legal advice. The rules about wills, executors and access to accounts differ from country to country, and in the US from state to state. They also change. Check what applies where you live before you act on any of this.