I've read spoilers for all roguelikes I got hooked on. Not until after having died over and over and over and over again though ofcourse
The first time I -really- dug into a spoiler, was when playing ADOM, and I just got sick of only being able to successfully play bashers...that in my hands, always died soon after early-game anyway.
I think ADOM has a steeper learning-curve than Nethack, but to put things in perspective, I saw one guy on the ADOM-forum that had refused to read -any- spoilers, and he spent 10+ years to be able to get a win.
It's even more rewarding when you discover things on your own, but roguelikes are so complex and mistakes so costly that quite frankly, I feel more than satisfied enough when advancing, succeeding and surpassing my own goals even when I have borrowed knowledge from other players.
It's just a matter of how many hundred times you are willing to re-roll to learn one new thing (if you are lucky) with each death. To me it came down to either, stop playing because I was getting fed up, or to read spoilers and keep playing.
Having fun is the only objective of playing singleplayer games! :-) And luckily roguelikes are so difficult, that even if you have read a spoiler, getting a win is respected nevertheless. Have fun!