"When doing trading" you mentioned right? Then it was on a exchanger/trading platform itself because obviously you will miss an action once there is a trend if you don't have any funds there. You can also consider to withdraw some as part of precaution.

If you always trades, using exchanges service is not totally wrong. You just have to understand the risks. Like you said, it's annoying to transferred funds anytime. Risky as it is but you have no other choice. So to minimize the risks, use the service of a reputables ones.

If your purpose is to hold it for quiet some time, then's it's more wiser if you considered to stored your coins on a wallet that you control your private key.