You ask how many days off you're entitled to after a bank holiday. The answer comes in two seconds, well phrased and precise — and wrong, because it doesn't know your collective agreement. Whether that can happen depends on which tool you're using: some look things up and cite sources; others answer only from what they learned in advance and can't check anything. They look the same — same field, same calm reply — but they aren't equally reliable. Knowing which kind you're using is the skill itself.

• It doesn't know YOUR reality. Your contract, your procedure, your prices. It answers generally and sounds just as confident — that's the most common mistake in a workplace.
• A real source, used wrongly. There's a link, and the link works — so nobody opens it. And then the source says something slightly different from what was claimed. A link is a reference for you to follow, not a proof.
• Multi-step calculations. A single figure usually goes fine. A deadline that has to be added up from notice period, weekend and bank holiday is where it comes apart.

There's no such thing as an unsure voice. It writes with the same calm whether or not it's on solid ground. Asking "are you sure?" isn't a check either — you'll get an equally calm answer back.

You don't have to verify everything. But anything that costs money, affects a person or leaves the building you should be able to find again somewhere else. If you can't, don't send it.