Because you are dealing with corporate customers, the person you want to visit must be at work, and there is work to be done at work. Don't let others delay your work in order to receive you. So be sure to make an appointment first so that the person you want to visit can set aside time to talk to you.
If you visit directly, the advantage is that the person who visits is not busy, so the probability is generally low. The bad thing is, you can't find anyone directly, so you come for nothing. Another situation is that your conversation is always interrupted, because people at work always have things to deal with, and as a result, you all spend time, and as a result, you don't have in-depth conversation, which is no different from not talking at all, which is not worth the candle.