Can a field be added to a custom form more than once?

@pat_paterson - Ditto what Skye said below, BUT depending on your use case, you can make it seem like there are multiples of a field on a form. You can utilize Label and Name and have it set similar to the below. The label being what shows to end-users. If you need to pull the results from the multiple different fields, then you can use a calc field to merge results. You'd have to thoroughly think through how you're structuring your data but just some additional options.

Field A Label: Marketing Campaign

Field A Name: Marketing Campaign - A

Field B Label: Marketing Campaign

Field B Name: Marketing Campaign - B

Seth - not sure whether my use case is aligned with your question, but I am researching whether a second instance of a field in a custom form can be added to the form dynamically? 

Example: 

Field1:  Item Description (+)

By clicking the + sign, is there a way to dynamically add

Field 2: Item Description (+)

By clicking the +, dynamically add 

Field 3: Item Description (+), etc.  

Thank you to anyone with any feedback that can help me research the above use case.