Solid advice and a good thing to keep in mind. Some things come to mind...

What if you have such a small amount on the exchange that the withdrawal fee would eat all of it? (Cryptopia has a 500k satoshi withdrawal fee for BTC. I started with 125k for trading...)

Which exchange are you referring to? CoinsMarkets? Lol, they got a bunch of my money, too but I made it all from trading and staking the 125k i previously mentioned.

Good luck out there!