I don't know how many people do this, checking exchanges on monthly basis to know their performance and know how to go about them. This is a source from Coinglass that shows the top cex that has done well this month.
some users may not have many accounts on exchanges. only have one or two accounts on the CEX exchange for trading purposes that they already trust and think they are comfortable with.
I don't think many people will check the performance of the exchange. maybe check when they have new tokens in their wallets that are planning to be listed on CEX.
it may be different for those who trade with an Arbitrage strategy. they definitely monitor how developments and changes occur in each exchange to look for opportunities.