When you're creating a product larger than one person can create, this is an excellent proposition. While “one person” may have had the original idea, we need many people to refine the idea and bring that product to market.
Books and consulting are all different beasts.
You can write a book by yourself. I advocate hiring a variety of editors, and a cover designer, maybe even more people, to create a great book, but you can do it yourself.
You can create consulting services and deliver them by yourself.
You might have more fun with other people (and I do!), but you can create and deliver it by yourself.
Every time you create something, you create intellectual property. That property has value over your lifetime plus 70 years according to general copyright law.
That's why I recommend writers retain their copyright. Aside from the obvious selling past your death, you don't need to ask anyone if you can use your material in a workshop or a talk or any other media we don't know about yet. You don't need to worry that someone else will use your intellectual property without your permission.
I've discovered people using the images from my books and articles without permission. Often, they had no idea they were doing something wrong.
I've discovered people quoting from my work without attribution. They didn't realize they should have credited me with my words.
I find these mistakes disconcerting and I work to be reasonable to fix them. Sometimes, I can be reasonable, sometimes not.
What I find much more troublesome is when a client feels they are entitled to my intellectual property. I've noticed this in several clients this year. There must be a new crop of lawyers out, just itching to grab IP rights.
I've had to cross out and renegotiate consulting agreements where the client thought they could hire me to create a custom workshop and they would reuse it internally. One of them wanted to reuse it externally. Uh, no.
My work for hire was the delivery of my intellectual property—a one-time delivery unless we had more of an agreement. Sometimes, we came to an agreement. I've also canceled several proposals because we couldn't agree.
I'm disappointed because I wanted to do the work. I was excited about this client's challenges and I was excited to work with the people.
However, I didn't want the circumstances of that work. When people have so little respect for me, for the time I've spent learning and creating my IP, for the time I would take to create a great experience for them, I don't respect them enough to continue a working relationship.
When companies pay you as work-for-hire, they pay you “enough” that it's worth your time to never be able to use your IP again. Even as an independent, I sometimes accept writing assignments that are work for hire. I can't republish that writing on this site, and I often have limitations on how I refer to it. That writing slides into obscurity.
If you create anything that your company doesn't own, do consider your intellectual property. As a consultant, your client does not own your IP. They do not have the right to republish it or use it again unless you have an agreement that they may do so.
(I realize this is an unusual topic for me. As I inch the consulting and writing books forward, expect to hear about these kinds of topics more often.)