I don't know about you but once an author appeals to me I stick with him/her. Sometimes its not even necessarily their writing that makes me loyal. It could be an interview I read or their own website that makes me draws me to their work. I like to get a sense of the person behind the talent.
If you are an author that has appealed to me both as a reader and as a person you can guarantee my purchase of your next book. Maybe this is not the right way to do things but I tend to ignore bad reviews of books by authors that I care about. I have mentioned that I have read all of Stephen King's work, short stories, novels, articles in Entertainment Weekly, non fiction about writing..... you name it I read it. I consider myself what King refers to as a Constent Reader. When a new novel of King's comes out I could not care less if the premier literary critic calls it a steaming pile of .....you know what I am at the store the day it comes out to pick up my copy. Now I will not say that I have loved every word he has written but when it comes to his work I like to draw my own conclusion.
My reason for liking Stephen King? He's weird. I like weird people who don't take themselves too seriously.
There are other authors that I consider myself loyal to. I have mentioned J.K. Rowling in previous posts. I will also always give Dean Koontz a chance although I am not as loyal to him as I could be. John Saul has my purchase whenever he comes out with something new. Most recently I have been reading Sarah Addison Allen's work and I really like the way she writes. It's fun and who doesn't like fun?
I consider myself loyal to an author if after reading their book I go back and purchase more of their past work.
I would live a rather boring reading life if all I read were novels by the same authors I am not saying that I strictly read these authors and no one else. I am just more inclined to choose their book sight unseen. If someone recommends a book to me by an author I am not familiar with I Google the authors name. Read about them and then draw my final conclusion after reading the book.
Although I tend to lean towards the horror/mystery/crime genre, if Stephen King started writing Historical Fiction I would read it or J.K. Rowling writes about fishing.....I will read it. Just because I feel they deserve my time (and money).