I am rubbish at taking my own photos, so I do use professionals although last year was the first time I paid anything for photos.
It was really interesting to notice that when I changed to a female photographer who isn't directly involved in any form of sex work, that my images changed in quality. They looked more like me, less brash, more natural even though they are quite polished images.
Polished doesn't mean overly shot, I always want my photos to be fairly close. I do put a few home-made ones into various galleries, so that it is possible to see that I'm not greatly different to the pro-shoot photos.
I would also agree with Amy that there is an element of 'new photo' excitement which galvanises clients old and new to rebook, plus a certain number of men who seem to think photos are for their entertainment.
I can also guarantee that one week after uploading the result of a photo shoot, I will receive emails from men who've never met me yet asking when will I be uploaded more recent, up-to-date shots. Perhaps they only just started looking?