<i>Specify date in format like 25/3/1987</i><p>Users will routinely ignore or misinterpret instructions like this. It takes an extra hour or two of work, but either do the three dropdown boxes or give them a free-form text field which is fairly intelligent with a suggestion that tells them how to phrase things and then attempts to discern their intent when they write things in a way which is not ambiguous.<p>For example, 3/25/1982 and 25/3/1982 and 1982 Mar 25 are all trivially recognizable and unambiguous. Should someone type in 3 4 82, two hours of work will let you say "We really care about your tax return being accurate so we want to check: is your birth date [March 4th, 1982], [April 3rd, 1982] or [something else?]"<p>You would additionally benefit from microcopy on this page to the general effect of "Your data is totally secure -- we use bank grade encryption [and blah blah blah]. You can review your return before we send it to the tax authorities."