First ask, who established the tradition? Did God found the tradition or did men? If God told a group of people to do something and to repeat it at certain times, then the remembrance is holy and good. God’s arrangements are designed to keep us safe in His paths.
If men established it, it may or may not be beneficial. For example, most people have a tradition of celebrating a wedding with a party. No where in the Old Testament does God command a wedding celebration. So the tradition is manmade. However, there is nothing wrong with it. In fact, Jesus, Himself, went to a wedding feast and made wine!
A problem occurs when people honor men’s traditions over God’s commands. Jesus said, to the Pharisees, “‘…laying aside the commandment of God, you hold the tradition of men–the washing of pitchers and cups, and many other such things you do.’ He said to them, ‘All too well you reject the commandment of God, that you may keep your tradition…making the word of God of no effect through your tradition which you have handed down. And many such things you do,’” Mark 7:8-9, 13. If a manmade tradition does not contradict God’s word, then it may be fine.
To learn God’s commands, let us be like the Berean brethren who, “received the word with all eagerness, examining the Scriptures daily to see if these things were so,” Acts 17:11. Let us also not add to God’s word by creating a manmade set of rules. We all have Christian liberty to act in love. “Where the Spirit of the Lord is, there is liberty,” 2 Corinthians 3:17. Simply stated: where the Scriptures are wide, we are wide. Where the Scriptures are narrow, we are narrow.