I use guides when I'm really stuck on something, because a lot of times it's something stupid I'm stuck on. For example, when I was in the Lakebed Temple in TP, I was in the room where you get the first key, and I could not figure out how to get it to save my life, so I had to look at the guide. Of course, it was as simple as shooting down the stone pillars from the ceiling with the bomb-arrows and I felt like a complete idiot
Most of the time, though, I try not to use a guide, because I find it more fun without it, and it makes me feel like I accomplished something.