As an info marketer with thousands of customers worldwide, I have delightful correspondence with hundreds of my buyers.

But from time to time, I also get some off-the-wall complaints.

Perhaps the most idiotic in recent memory comes from ST. She recently purchased my e-book "Writing for the Christian Market" and then immediately asked for a refund.

Reason given? The book was published in 2007. Displaying stunning lack of understanding of the value of content, ST lectured me as follows:

"I must say that I have been very disappointed that the book is from 2007. I keep reading it wondering if any of it is still relevant or if the resources and publishers are even still in business. So much has changed in the past 7 years. Magazines have folded, blogs are commonplace, and again, I'm not sure if this content and ins in the market are still valid.

"I wish the promotion materials would have been forthcoming with this information. I doubt I'll ever buy a product promoted by Bob Bly again. The price seems too high for such a dated work."

I immediately typed this reply:

"Your statement that a book published in 2007 is outdated and worthless is shocking in its inaccuracy, especially considering that you are a Christian writer or aspire to be one.

"If your logic is correct, then we should both return our Bibles to the store or site where we purchased them for refunds, for of course the Bible was published before 2007 – and therefore, by your logic, is outdated and of little value.

"With all due respect, you are deeply misinformed. There are two categories of content: timely and evergreen; the latter is information that does not change with age or time. The Bible falls into that category, as do thousands of how-to books and videos.

"The advice in this book is completely accurate. It applies as much today to getting published in the Christian market as it did in 2007."

Yes, ST is right that in any older publication, some information becomes dated.

For instance, I have written dozens of how-to business books over the last 3 decades or so.

I am sure that the addresses, phone numbers, and web site URLs for some of the resources recommended in these books have changed or that the resources may now be unavailable.

But that's a minor detail. It doesn't speak to the core value of my books and information products.

In many instances, way more than 90% of the advice in my books is completely accurate and valid 10 or even 20 years after the book was published.

This is especially true with books on "evergreen" topics like leadership, success, small business, and writing.

It is less true with books on topics that evolve over time, especially those involving technology, and of course that includes marketing.

But here's the thing: an older book on an evolving topic like marketing obviously does not cover new marketing channels developed after its publication; e.g., there is nothing in my Copywriter's Handbook on Pinterest or Google+.

But 99 times out of 100, that does not invalidate the ideas and tactics the book does teach.

In the case of our Christian writing e-book, some of the publishing outlets it lists have changed: old magazines have folded, new ones have popped up, various blogs and web sites are now markets for Christian writing.

But virtually everything else the author, Terry Whalin, says about how to write for the Christian market is still spot on. And with over 60 published Christian books to his credit -- and experience as both a book editor and literary agent -- Terry knows more about writing for this market than almost anyone around.

Sadly, aspiring writer ST won't benefit from Terry's incredible knowledge and advice on how to write and publish for the Christian market ... for the silly reason that this book is 7 years old.

When it comes to my feelings about ST's e-mail to me, I close by quoting Bugs Bunny, who famously said: "What a maroon!"