This is probably among the most basic things which anyone that uses cryptocurrencies should know, if it's not in your personal wallet it's not yours yet, as simple as that, but surprisingly enough there are actually people that really think that their tokens/coins are totally safe in exchanges, if you ask those people why are they so sure and feel safe, most of them will probably just say because they trust the exchange or something like that.

Seems to me some people tend to forget previous incidents regarding exchanges getting hacked rather quickly, BitGrail hack that during the incident millions of XRB(Rebranded and known as nano now) got removed from their wallet and the cryptopia hack that happened recently and it wasn't even this exchange's first time that experienced an incident like this and then again people trusted this exchange enough to keep their funds on there, why would anyone trust an exchange with all those previous fishy incidents (like the time when they were having something around 1 month or even more for a simple withdarawal action) and such really?

I'm not talking about the amount that you are trading daily or weekly obviously, this is about medium/long term holds, the tokens, coins or even stable coins that you're not going to exchange them anytime soon, so just don't go ahead and put your life savings on exchanges and use them as a bank no matter how trusted and reputable that exchange is, you can only use your personal wallet (preferably offline) as some kind of a bank, even if we assume that one exchange is really trusted and they're not going to go offline the next hour or tomorrow there's still a chance (even if it's really low) that the exchange that is trusted by you and many others just gets hacked and all your funds on there goes poof.