TLDR: Ask irritating questions, you could end up saving the company money and time...

I’m working on a project where we are integrating 2 legacy web applications with each other.

Business Analyst/Project manager (BA) : Save all the contact details of the selected firm in application A into the database of application B, then expose that data later so that we can output it into the document when the user generates them.
Me: Seems a bit excessive, there’s even a fax number, nobody uses that anymore, are you sure we need all that?
BA: The old document has all that information.
Me: Please just check with client that witch fields are still needed in the document.
BA: Ok, fine, but it’s probably a waste of time…
BA: * Talks with client on phone for 10 minz *
BA: Ok client stays we only need the Lodgement Number on the document.
Me: We already store that and populate it in the document.
BA: I had budgeted 2 days labour for all that, you just saved us a lot of money!