A date proves one fact and no others. It records when you last had a reason to believe the thing beside it. That is all. It is not a freshness guarantee, it is not a signature, and it cannot tell you that an address file written in March is still describing anything real.
What it does is change the question you are asking. From your chair you cannot answer whether your copy of an awazon market address is currently correct. You can answer instantly how old your copy is. Age is a question with a knowable answer, and it is enough to decide whether to lean on the thing or go and refresh it before you do anything else.
What to write, and where
A month and a year is enough for slow moving things. A full date and a rough time is worth it for anything tied to money, because a rate note without a time is a number floating in space.
Write it next to the thing, not in a separate log. A log gets lost, gets out of order, and cannot survive the item being copied to a new place. A date that travels with the string it describes stays useful for as long as the string does.
- Where the thing came from, in three words, matters as much as when. A line reading "from a signed notice, saved in July" tells you what a bare date cannot.
- If you refresh an item, replace the date and keep the previous line rather than deleting it. Two dated versions that agree is quiet evidence. Two that disagree is a warning you would otherwise never have seen.
- Never date something with the day you copied the file. That records a file operation, not an act of checking, and it will make stale material look fresh.
The trap of the refreshed copy
Copying an old note into a new file and dating the new file today is the most common way people fool themselves. Nothing was checked. The characters are exactly as reliable or unreliable as they were before, and now they carry a date that says otherwise.
The date belongs to the act of verification, not to the act of writing. If you did not go and look at a source, the date does not move. This sounds pedantic until the first time a nine month old string sits in front of you wearing a fresh timestamp.
Dates on things that are supposed to expire
A few items are useful precisely because they run out. A delivery window is a date with a purpose. Once it passes, it has told you what it exists to tell you, and the line can be crossed out rather than refreshed.
Keep those separate from the material that needs refreshing, or the two kinds of expiry blur together and you end up either chasing dead lines or ignoring live ones. One list of things to renew and one list of things to watch pass is a small amount of structure that pays for itself.
How old is too old
There is no honest general answer and anyone offering a number is guessing. What can be said is relative. Anything you have not touched since the last time you actually used the market is older than your experience of the market, and should be refreshed before you trust it. Anything that predates a change you know happened is worthless regardless of how carefully it was written.
The practical version is to look at the ages before a visit rather than during one. Age checks take a minute when nothing is wrong and are impossible when something is.
Questions that come up
What if I have no idea when I wrote something down?
Treat it as expired. An undated item has to be trusted rather than judged, and trust is the expensive option. Refresh it, date the refreshed copy properly, and you never have to have this problem with that item again.
Does a date help if my copy was wrong from the start?
Not directly. What helps there is a second copy collected separately, which is covered on the next page. A date tells you about age. Independence tells you about correctness. You want both and they are not substitutes.