I had a DEX approve 1000 USDT. I then traded 1000 USDT. The next day I want to trade another 1000 USDT from the same address, but the same DEX asks me for approval again! On Etherscan Token Approvals my address has 1000 USDT approved for this DEX (including version). Now the questions:
Why does it ask for approval again (same address, same DEX version)?
When 1000 USDT is approved, it means I can spend no more than 1000 USDT at a time for as many times as allowed by the balance of my account?
Is there any point in approving less than the maximum amount? Because if the answer to the second question above is “yes”, then what prevents a thief’s bot from running the withdrawal transaction a few (dozen) times instead of just once?
On the other hand, if an approval for an amount is only valid once, then why do DEXs say that you need to approve a token just once, why do well-respected people advise to revoke approvals and why does the Etherscan Token Approvals site menacingly states “$xxx at risk”, when all these approvals have long been used?
Thanks a lot in advance.