Is there a way to check the date I bought games on my Steam library? I bought Garry's Mod sometime back in 2012 and I want to see the exact date (day, month, year). Is there a way to do that?
There may be a limit on how far it goes, but my Steam transaction history goes back to December 2009.
To view your own transaction history from the Steam client, click on your account balance in the upper right of the client to bring up the account page. Then select "STORE TRANSACTIONS" and then "SEE ALL" at the bottom recent transaction list.
If you have no account balance, you can also view your history by going to the "Steam" menu in the top left, selecting "Settings", clicking "View Account Details", and then clicking "Purchase History".
You can also just navigate to your game library and see the date each game was purchased (right beside "Install"):