How can I check how much I can spend on my EarnIn Card?

You can look on the homescreen of the EarnIn App and you will see Available. This is the amount you can currently spend on your Card. It represents available cash in your account and your issued earnings

If you stop routing your direct deposit through EarnIn, you will not be able to spend available earnings from the EarnIn Card. However, you will still be able to transfer out earnings to your linked bank account.