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 believe that at this time we should only buy and invest in the short term, you should not hold long any coin, at present bitcoin prices are recovering but recovery is not strong and bitcoin prices will be able to reduce strong at any time. So at this point I think you should only invest in short term and always have a specific trading plan.