Each CS:GO skin has a "wear value" (frequently incorrectly referred to as a "float value"). This number is a percentage (as a decimal between 0 and 1) which indicates how "worn" an item is. 1 is the most worn an item can possibly be, and 0 is the most pristine.
When we display inventories, we pull the data from steamcommunity.com. We use the same interface that the Steam Community inventory page uses, which unfortunately does not include an item's raw wear value, nor certain data about its stickers.
In order to get the wear value and sticker data, we have to use another interfaces called the "WebAPI". Unfortunately, this interface is extremely unreliable and only works some of the time. As a result, we are unable to immediately get this data.
Once you deposit an item for sale and it's traded to our bots, it is queued for a wear update. The WebAPI includes wear and sticker details for all items owned by an account, and each one of our bots attempts to download this data every 10 minutes.
There is no fixed schedule; rather, each bot simply has an internal 10-minute timer. Once this timer elapses, it tries to download the WebAPI data 10 times. If successful, it updates wear and sticker details about each item in its inventory. After this time, the wear and stickers will appear on the OPSkins website.
If the bot is unable to download the data after 10 attempts, it will give up and try again 10 minutes later. In our experience, it takes the longest to obtain this data during peak hours.
In a nutshell, it's hard to get wear and sticker data from Steam. As a result, our bots each try to do this every 10 minutes. Once they're successful, they will put the wear and stickers up on the website for your item. This may take some time, so please just be patient.