It’s not a bad idea to keep your crypto on an exchange for most people.

Managing your own wallet is hard, especially for newbies.

If you’re trying to transfer $50 of ETH to a wallet from an exchange, it will take you around $20 to transfer it, which is not a good idea.

Keeping your wallet safe is also hard for a lot of people. You need to store your seed-phrase somewhere safe and offline (if it’s saved somewhere online, consider it compromised).

A lot of people are more than capable of doing all of this and if you have thousands invested, then it’s a good idea to store it safely on a wallet, and potentially to even get a ledger. If it’s less than that keeping your crypto on an exchange is not a bad idea.

Also it depends on which exchange you keep your crypto in? Binance, Coinbase, Kraken or any of the big ones are safe and they have insurances against hacks and lost coins.

If it’s a shady exchange then don’t keep your crypto there!