does it vary for different coins? I'm asking because if I want to day trade I want to make sure its doable. Someone told me it takes a long time to have a buy go through and a sell.
Time taken for a buy/sell mainly depends on the token involved and the price. With exchanges bringing in sophisticated interfaces for faster trades, only a few have short delays in updating orders. Other than this, depending upon the price of the buy/sell order, you should be fine with your day trading activity.