Good luck finding a FWB. I have known many who tried but few can pull it off. Surf some relationship message boards and you will find many horror stories. Someone usually develops deeper feelings.
"Friends-with-benefits" works when the FRIEND part comes first and the "benefits" (sex) way later. In my experience, these relationships started off with NO sexual intentions or expectations from the very start. I am recalling one particular case where I was roommates with a couple, and they broke up while we still had a few months left on the lease. For a time, one member of the "ex-couple" was having sex with both of us, then when the other member moved out, the remaining one and I continued to have sex off and on for the next few years, while becoming involved with other people. We did not go about it by LOOKING for a "friend with benefits". The adding of sex to our friendship WAS a form of "deeper feelings", but we never became an "item" or "partners" or whatever you want to call it.
I think if someone goes out LOOKING for a "friend with benefits", usually meaning "regular sex partner without the day-to-day contact", they will find that they got themselves into something other than what they had in mind.
I'm sorry to hijack the thread based on such a small piece of the OP's topic.