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.
Holding your coin on a exchanger is just fine as long as the market is very reliable, you can always look on the history of the exchanger if there's an issue before or ask a reliable person on what exchanger is the best market to place your coins.