Prospective clients often ask for samples of work I’ve done in their industry. This is problematic for several reasons.
Writers (unlike designers) do their work at the beginning of a project. I am not around at the end to obtain a sample. Some work, like website content, just isn’t conducive to having samples. Although I can take screenshots, screenshots are better at showing design than copy. When website links break, the copy goes MIA.
Samples may not really represent a writer’s work. Samples represent work after it has undergone mutation in a process of committee and legal department review. I may have written something wonderful (or terrible) but very little is left.
Writers don’t control the design of a piece. If it looks hideous, it makes a hideous impression, no matter how great the writing is. I do not want opinions of me to be based on the work of someone else. Only fair, right?
I do most of my work under NDAs for agencies. I have to hide my involvement in my most prestigious and impressive projects.
Finally, samples are pretty much irrelevant. Every business, even in the same industry, is unique. Good writers have the ability to learn the key aspects of a business and its industry very quickly.