Is it time to hire a web designer?

I've been doing SEM for a few years and I've always designed my websites. I'm not a professional web designer though and I must admit not very talented. I use MD and I have basic html knowledge. Sometimes I spend many hours day after day modifying pages until I realize they still don't have a professional look. This is really frustrating, plus it sometimes seems like such a waste of time.

The reason I'm reluctant to hiring a professional web designer is not the extra cost, but my fear that the new design might not be search engine friendly, or that I might not be happy with it. There's also probably the fear of making this change since I've never had someone design my websites before.

What's your experience regarding this issue? How many of you in my situation have made the change and how do you feel about it?

Thanks for any input.