How long does the LT Fuel Trim take to mean something?

I changed the 12V battery (very) recently. Today while playing with a new Autel AP200 I noticed that the long term fuel trim was reading -0.8%. Figured that the car probably set it to 0.0% when the old battery went out and the new one went in. So right now this figure only represents about 100 miles of driving. How many miles might it take for that value to become meaningful? Or put another way, assuming the 12V hasn't been messed with, how many miles are reflected in that value? I'm guessing that the information from 20k miles earlier has been flushed out and only that from the last couple of hundred or thousand miles remain. (Because if there is a problem now one wouldn't want to wash it out with data from long before the problem arose.)

I don't have any reason to think there is an issue which should be causing problems that would be reflected in the LT fuel trim, I'm just curious how long it takes to be a useful value.

The manual indicates that a pretty large range of fuel trim values are acceptable. For a 2nd generation in good health is that wide a range of long term fuel trims actually observed, or are they typically a lot closer to 0? I recall (imperfectly) a Scotty Kilmer video where he was looking at some Toyota or Lexus and noted that the LT fuel trim on that car was really small, like less than 1% one way or the other, and my impression was that was pretty much what he expected to see.