Why? Do you consider yourself less of the creative type and more of a worker or business man? Do you just not have the funds to create your own sites, or too busy working for clients? If you're a good SEO who has been around for a while, you've seen the revenue that you've created for your clients, many who have shitty sites you could have come up with. P.S. If you're an established SEO who only works with big clients, this question doesn't apply to you.