What's your opinion on using walkthroughs?

I use them often, then hate myself for using them.
Seriously, i can't count the times where i searched for help when playing the Longest Journey.
On the other hand, i'm quite proud for having finished Portal, Portal 2 and Braid completely walkthrough-free.

I sometimes use guides because I have such a huge Steam backlog and not much free time. This lets me play through and enjoy the next game

I use them when I get to the point where I go in a pattern. Run to barrel, run to door, run to gate, run to entrance area, run to barrel, etc.

I avoid them. Although, I don't have too much time to spend playing games, unfortunately. And sometimes I stuck in some parts of the game and it's boring to 'lose' too much time in something that you're supose to be enjoying.
Ans sorry abou my shit English xP

Same as you, I refer to WT when stuck.

I'll watch one if I'm stuck or if I have no intention on playing the game and I like the commentator. Most of the times its not story related and achievement related when I do use them.

Try not using a walkthrough for Mirror's Edge.

There been alot of GBA games in the past that I played only using walkthrough, even when there was no problem (usually because I wanted to 100% the game) now I feel really stupid, like it really ruined the experience, now I might use walkthrought if I'm really really really desperate beyond any reason, but I don't remember the last time I did use walkthrought.