Do you need a form that lets users add in multiple fields to the same section? Here’s an example: If you’re looking to let your user submit a list of names e.g. for a sports team registration, or to list past work history and qualifications in a job application form, repeater form fields are a necessary function of your form builder.

They allow your user to submit as many details as he or she wants to a certain question.
Why does that come in handy? Because it saves you hours of work thinking about every possible solution. Also, just imagine the amount of form fields that will drastically lengthen your form. And even then you will get the occasional users who do not fit into your categories and you end up contacting them individually.
Repeaters let your visitors dynamically add multiple form fields whenever needed, so your form gets leaner by still offering the same possibilities.