This is a lesson I learned. For sure it is "cool" and "trendy" to buy a game by launch because you will be part of the trend. Most console games and PC games that are mainstream causes $60 dollars at launch and that is an incomplete game and it will eventually have DLC which you will also pay for. It is better to wait for the games to release their "Special editions" or "Remastered editions" of the games which is usually 1 to 3 years later because you will get the game for just $10 to $25 complete with the DLC content and with the bugs fixed. Sometimes the special editions also have additional content originally not on the game.
Well this is just a good live and learn little tip that I am sure I still fall for more than I really think that I do. It seems that the ability to just wait a little bit usually pays off pretty well in a lot of different areas.
I think I will only buy a game at launch if I am a popular streamer at Twitch that makes money from gaming but I am just a regular gamer. My internet connection is too slow for me to be a streamer. So waiting is still the better option for me. The special editions are not only cheaper but they have better graphics than the launched versions. When games flop, they wont have special editions but you can buy them at cheaper price.
I never pay extra for the collector's editions, especially since what they come with is often just pixels (a special mount, etc.). I used to buy at launch when I played competitively, because I couldn't afford to get behind. I don't do that any more. It's true that you can save a lot of money by waiting. Games often go on sale fairly soon. You may even be able to get a good deal on a bundle like the Battle Chest offered by World of Warcraft that includes all the previous expansions for one set price.
I also noticed that buying a game at Launch and buying the dlc and expansions consumes a lot of space in the hard drive. The files of the game are more compressed when you buy those complete editions. Complete editions are not only cheaper but they also have less bugs.
I regret buying such games just to follow the hype caused by the Internet. When I get such games, I play them for a couple of hours and will most likely stop after that. Nowadays, I rarely buy new games since there are so many unplayed games in my Steam library.