I sometimes receive notifications that I can expect a delivery in a 2-hour window such as "between 12:07 and 14:07".

To quote to the minute shows a failure of understanding of what an approximate range is, as well traffic and logistics.

It's a 2-hour window of imprecision. Quoting to the minute shows a deep lack of understanding. Quoting to 5-minute intervals is just about acceptable. To 10- or 15-minute is more appropriate significance. But honestly, in this case, to the hour is just fine.

Received a message telling me to expect a delivery "between 09:50am and 2:45pm". To their credit, they avoided quoting the estimated range to the minute (or to the second!), but the implication of quoting such limits to a precision of 5 minutes is nonsense given that the window of uncertainty is 5 hours.

When developing software systems, understand your domain and understand your users. Your users are human, so go with "between 10am and 3pm" to sound like you know what you're doing.

@kevlin The problem with saying between 10 and 15, is that if they then arrive between 09:50 and 10:00, there will be people who'll complain that they arrived "too early", and if you then instead say between 09:00 and 15:00, then people will complain the window is too wide and "imprecise".

The fake(*) precision is part of the message, that it's specific to your delivery and that you shouldn't bother contacting customer service to get a real time window.

*: see next reply...

@mrotteveel @kevlin Indeed. That 09:50 figure being to the nearest 5 minutes is not, of itself, a problem. It will be calculated on the basis of the courier leaving the depot at time x, and having a number of journey segments of predictable length. So it's the earliest time that it might arrive. The 2 hour, or 5 hour, finger-in-the-air value? Yeah, it's adding that on and keeping the precision that's the problem

The expected arrival curve is nothing like a Bell curve