For some games. Like, Animal Crossing and Harvest Moon, I like to plan things out. But for Zelda and Mario and such, I like to figure things out for myself.
And the only game guide I've ever bough, and ever will, is the Mother 3 Handbook. $20 for love - in book form.
And I also bought the Pokemon Snap game back in the day, even though I didn't own the game. Screwy, ain't it?
WAAAAY back when I used to use strategy guides. I believe I still have strategy guides for Banjo Kazooie, DK 64, Pokemon yellow/blue/red, Ocarina of time, Majoras Mask and Links Awakening.