I am trading cryptocurrency in Korea,and I am using two different exchange platforms: a exchange called Dove Wallet and Binance, due to liquidity and also a price difference called Kimchi Premium. Is it common to use two or more exchanges?
It is very common and I know that many people have accounts on more exchanges, because for some of them you don't need to pass kyc verification and for other exchanges you must pass it.
Some exchanges have better volume or lower fees, and there are other decentralized exchanges like Bisq and people can use all of them for trading.
I don't however recommend anyone holding Bitcoin on exchanges because next hack is just around the corner.