This passage is in the context of taking the Lord’s supper.
However, personal examination is something that you should do more often than that.
The idea is that you should recognize sin in your life that God has been dealing with you to get out of your life.
In 1 John 1:9, you confess your sins so that God can cleanse you of your sins.
He wants you to confess and forsake them [Prov 28:13].
We know that we won’t be sinless.
Nevertheless, we have certainly quit many sins that we used to do without even thinking about them.
And we should continue to grow in this grace.
According to 2 Cor 13:5, you are also to examine yourself, “whether ye be in the faith.”
You want to be absolutely sure that you are saved.
It is common for some young adults to recognize that the profession of faith they made when they were children was not salvation.
Often, as adults, they respond to the gospel because, upon personal examination and conviction of the Holy Spirit, they realize that they aren’t saved.