Trading become a part of my life. I cannot even realize what I will do if I quit doing it. However, you can exit trading when you urgently need fiat.
It is you who must make this choice and that there is no one other than you who can motivate yourself to either continue doing trading or to quit it. If you are really in a mood to quit trading, then the best time to call it off is the time when the market value of the crypto coins is significantly higher and that by selling your coins, you can then get a lot of earning which you can then use in some other investment.
It is up to your desire, if you are tired of trading and has earned or made a lot of profit or huge profit then you can wait and stop trading as you are looking satisfied now and want to stop or exit trading. You need to sell out the last remaining coins that will earn profit for you and this will be your last profit. After that you do not have to buy more coins as you do not want to trade more.