validation - Mark input in forms as required even if all input is mandatory?

I looked up many questions and answers here regarding labeling mandatory input fields. The de facto standard is an asterisk * to mark input as required. Also the common approach is to mark the required input as such.

My questions are:

• If all input in a form is required (or only 1-2 fields are optional[1]) - does it still make sense sense to mark all of them as required?


• Is a caption like '* = mandatory input' still needed then or do people know what the asterisk means (balance b/w helpful information and added visual noise by the caption)?

[1] Just highlight the optional ones as such?

Answer

If no fields are optional, it would make more sense to have a message on the page saying all fields are mandatory.

If a few are optional, it would make sense to mark them as optional. I would use something different than an asterisk for this. The word "optional" in italics next to the form element is typical.

To be safe, you should still include a message somewhere explaining that * denotes a mandatory field. While it's a pretty common usage, it's not universal.