Does an audited protocol have to be safe? Many people can't answer!
In 2016, The DAO was attacked due to a reentrancy vulnerability. Ethereum responded with a hard fork, while the original chain that did not fork continued as Ethereum Classic (ETC).
Contracts that have been live for a long time and have been tested with large amounts of funds are generally considered more reliable, but that doesn’t mean they’re free of vulnerabilities.
Invest only what you can afford, and leave yourself some breathing room.
$ETH 1895.86(-3.16%)

Just jotting this down—make your own decisions about buying and selling.