At what point do you buy QSS when playing a Malzahar

id say dont buy it if you are mid, unless you are the highest priority for his ult, id say adc is the only one.

probably about when getting a pick would translate into a big objective for the enemy team. also depends on whether youre ahead of or behind the malz

I am not going to lie he scares me. if i face him in lane i get it second thing after my first item + lv1 boots.

By level 6 if you're an AD mid champion. It basically means that unless you royally mess up, he has no kill pressure on you, and you can potentially upgrade it to the very nice Merc Scimitar.

i'd get it after first two big items, to ensure you deal damage

I probably wouldnt but it unless you know you'll be focused in teamfights. It's not very gold efficient and keep in mind malz has more than enough damage to kill you without his ult.