The veteran people on crypto tend to say that you should keep your coins in your wallet, never on exchages. However if there is a strong downwards movement on a coin and you want to sell to buy latter at a cheaper price it may take quite a bit of time and fees to move it. What is the right strategy?
I save more than 30% currency's on my exchanges: HitBTC/Binance/Kucoin. And I think nothing bad in this not, if you have 2FA authentification