Don’t pay full price for games on Steam, you can almost always get a small discount and for older games if you wait a while you can usually get very large discounts. Make an account on IsThereAnyDeal. When you see a game you want on Steam add it to your wishlist and use the lowest sale price to figure out what you want to buy it for.
When a game comes on sale randomly you can get an email notification. And when there is a big Steam Sale, you can see which games are actually discounted more than usual. You don’t usually have to wait for Steam Sales because the same games will go on sale at other random times, or go on sale on other sites that sell legitimate Steam keys. But it’s worth having a wishlist ready during Stream Sales because most of the games on your wishlist will all be on sale at the same time.
Make an account on IsThereAnyDeal and start a wishlist with the games you want. You can see the cheapest price it’s ever been at on Steam and other sites that sell legit Steam keys. Then if you set target prices for everything, when the Steam Sale starts you will see which ones are actually discounted to the level you want.
Most games on Steam are discounted pretty regularly throughout the year at random times. During the Steam Sales the discounts aren’t always better, but most of the games on Steam are all on sale at the same time. Usually for my wishlist over half of the games have some kind of discount during one. Some developers/publishers put all of their games on sale at some other random part of the year, for example Square Enix might completely skip the actual Steam Sale for Final Fantasy titles, but then randomly have every game in the series 50% off some other time.