A few prefer one over the other. Some prefer both. What if you can't decide from neither? This is one of those choices you make that can alter the universe. Haha, relax guys, it is not that big of a deal. It's like some people like vanilla, some like chocolate. It's just a matter of preference. And of course money. HJ are a lot cheaper than FS. The ending for both is the same. It's just a matter of how you get to the finish. Time constraint also play a role. Sometime you need something quick. You have other things you got to do. Then there are times when you got all the time in the world. You can relax and make them kick you out. My experience has been to use the wait and see approach. There are several ways decide, but the one that works for me is when I'm right there in the situation. I don't have a mindset when I go to a massage parlor if I want just a HJ or go all out for the FS. I decide after I spent some time with the masseuse. No, it's not just how she looks. I don't really have a preference. She can be tall, short, skinny, chunky, or whatever race. I just like girls. Of course I'm not going to get hard if she looks like she got hit by a bus. So once I get in the room and interact with her, I make my mind on tug job or bagging the home run. I just pick up on the vibe if she would be a good lay. Am I accurate 100% of the time? Of course not, but I am close to it. I've changed mind in the middle of the sessions before. So I would still count those towards my accuracy. With time, you can develop the feel for it. But if you don't want to waste your time or money; read the reviews from veterans or this blog.