for me wallet is the best place to store my tokens or coin because you have access to it anytime any moment and what one i faces is that any time my coin is on exchange i don't feel resting .. ie i feels restless because i will be thinking they might hacked the exchange anytime despite i have applied 2FA and all security methods. the second reason why i don't like my coin to be in exchange is that some times i may likely trade it another exchange but since is already in one exchange to move it will be another fees and reduction of coin or tokens.