Some games essentially require it. For example, Majora's Mask is nearly impossible to 100% without a guide. When I was a kid, I had all the time in the world to figure things out. Not so much anymore. I'm not gonna spend hours upon hours trying to figure something out. I'll try it a few times on my own and if I have no clue, I'm not embarrassed to admit I'll open up a walkthrough.

Only if I realllly cant get it

This sums things up.

Only for collectables

No, because I feel like I'm retard if I do so, or that otherwise I wouldn't have been able to complete the game, at all, if it wasn't for the walkthrough and not for my gaming skills.

I felt like crap with that over Dark Souls 2, but on my defense, the game pulled some Gamefaqs crap over offline players like me.

If you have completed PT then your answer is yes. Some puzzles were just plain fucking stupid.

Oh, yeah, this too. I would have never figured out by myself how to write HELL or the ten-steps thing.

I'll try to figure things out by myself, but if something absolutely stumps me, I'll resort to a walkthrough.

I remember doing it for one of Other M's ridiculous pixel finding sections. But I don't usually use them until I'm done with the main quest. I use walkthroughs for end-game sidequests quite often.

This pattern of mine led to some frustration with FFXII though when I learned that couldn't get the best weapon because I opened random chests during my regular game.

A little known fact is that PT's alternate title was Why We Need Walkthroughs: The Game.