Buy it; 1) Its Daily sale 2) Flash sale 3) Community vote 4) "It's the last day of the sale" - Sloppy Seconds
Dont buy; 1) Normal steam discount in which it can go lesser when its in Daily/Flash/Community vote
AND DO NOT BUY GAMES THAT YOU WONT BE PLAYING OR ARE NOT INTERESTED IN IT JUST BCOS ITS SO DAMN CHEAP.. BUY GAME(S) THAT YOU WANT AND ARE WILLING TO INVEST YOUR TIME IN PLAYING IT INSTEAD OF JUST SHOWING HOW MANY GAMES YOU HAVE IN YOUR LIBRARY OR JUST BCOS IT GOT TRADING CARD, seriously.. (Sorry caps, just want you all to OPEN YOUR EYES and not go "OMG ITS CHEAP, ILL BUY IT AND KEEP IT FOREVER IN MY LIBRARY UNTIL I DIE AND LET MY KIDS PLAY IT" well.. anyways..
Enjoy the summer sale guys :) and if you do buy something and you're satisfied with it, don't be shy to share it below, show us your joy!!
Is the game daily deal? - Yes, buy it. No, don't buy it. Is the game flash sale? - Yes, buy it. No, don't buy it. Is the game community vote? - Yes, buy it. No, don't buy it. Is it the last day of Steam Summer Sale? - Yes, buy it. No, don't buy it.