If you wish to hold some coin then use exchange only for during exchange. Just exchange your coin and transfer on your personal wallet that you have controlled. Specially you can use hardware wallet.
Because many exchange hacked buy hacker. Many people loss their capital by hack.
So please don't hold your coin on exchange for long time.
Off course putting anything on the exchangers is very risky. However there are some of the coins which are very volatile and we may need them on the exchangers all the time to swing trade by putting them at the stop-loss order thus it gets locked out. But that much risk is needed. To avoid being hacked or stealing then we should always use all the possible authentication systems that are provided by the exchangers. For example, 2FA, SMS verification, Email Verification. This way we can make it far more strong.