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.
I strongly believe that you should not invest long term at this point, you can see that bitcoin prices are constantly fluctuating and difficult to guess, the market is bearish in the long term, because So we can only know the bitcoin price will decrease but can not know exactly at what time. So if you keep long term coin it will be very dangerous and very risky if the bitcoin price drops sharply.