I have most of mine on an exchange because I'm getting paid interest. Has there ever been a time when an exchange like Binance for example, steals your funds or gets hacked and people lost money?
I don't think it is a too bad idea to leave our coins on exchanges, but make sure the exchanges have good history and are friendly to their members. Of course, no exchanges are secure enough, all exchanges are possible to be hacked. However, several exchanges want to refund their members' money once there is a hack. I am sure Binance is one of the exchanges that have responsibility if there is a hacking case. So, I think we have no reasons to be so worried about our money. But never put all our money on exchanges, just put the amount of money that we can afford to lose.