Should an ABAP CDS be 1:1 to a business req?

As a beginner using CDS I have one basic question.

While creating CDS should we treat it like a report that satisfies one business requirement or should it be open to enhancements?

For eg. Can I use an existing view defn and extend it to hold more fields instead of creating a brand new CDS if the selection criteria is more or less the same. 

What are the consequences?

Thanks.

Meera