I only ever used it for MM because I wanted to get all the masks and 100% the game. Other than that, no... I never used one.

I've honestly never used a walkthrough for the games I've beat in the series.

I know for fact that I've completed both of the oracle games without a walkthrough, because in 2001 when those came out we didn't have a computer or internet connection yet, so no walkthroughs for me. Same goes for Link's Awakening. (Although after I found out about the 'true ending' I was tickled....)
Maybe my creativity or problem solving skills withered over time (maybe I just go too lazy to pour hours of trial and error into a game, now that I've got stuff to do! ;P), or maybe some things in oot are just obscure, because I really didn't know what to do after certain points of the game.
I have one savefile in WW going blind and one I played with a walkthrough, because I like going in and see what I missed the first time.
I tried to do a blind run of the original nes game on the 3ds virtual console, only help allowed was the official (incomplete) map that came with the game + manual. I printed the map out and spend hours drawing in the rest of the map as accurately as possible. Fun times. I got pretty far but never completed it, though.
Spirit tracks I played blind up to the final battle, and just before that I got out a walkthrough and went onto a massive collectible/fetchquest sidetrack.

So it's mixed for me, most of the games I'm pretty sure I can beat without help, 100% completion is another thing though and instead of walking around aimlessly I usually use guides to achieve that.

Didn't use walkthroughs for any of them, but I never 100% any of them.

Never used it, it really kills a bit of the fun if you use.Having said that, the first time i played Majoras Mask I got so gigantly stuck on it it took me months to finish it.

Only used walkthroughs for collectibles and other shit

I like to 100% on my first play through. I need a walkthrough for that. I enjoy it actually. My wife reads the walkthrough while I play through it. The second time playing through I don't use walkthroughs, though I still try to complete as much of it as I can remember.

No, I've never used a walkthrough for my first playthrough on any Zelda game. Not even Zelda 1 and 2.

You most definitely don't need to be a genius, you just have to pay attention to game. Especially in games newer than Wind Waker, when the series becomes more and more linear, a walktrough to complete them is totally unnecessary.

When I beaten them though, I could look at a walkthrough, just to see if I did everything the best way and if I missed anything even though I try to 100% everything beforehand. I have most of the official strategy guides.

I got the Piggyback guide as a pre-order bonus for the Wind Waker (and lol, it was only 49,99€ with OoT bonus Disk) and used it to 100% the game. That's also the only 3D Zelda game that I ever 100%ed (second time with WWHD).

I remember that I needed forever to finish ALttP when I was 5 or 6, but that experience plays an important role why I love gaming.

Just WW, seemed like a chore trying to find all heart pieces without one.