Numbers 6:1-2 Then the Lord spoke to Moses, saying, “Speak to the children of Israel, and say to them: ‘When either a man or woman consecrates an offering to take the vow of a Nazirite, to separate himself to the Lord,”

Nazarite is from a Hebrew word to consecrate or separate.
This is a serious vow of dedicating one’s self to the Lord involving avoidance of wine and vine products, cutting your hair and then letting it grow, and avoiding dead bodies.
I assume the person taking the vow assigned a time length on it.

Christianity is a Nazarite vow of sorts!

In writing to the Corinthians, Paul began to instruct them on unequally yoked relationships.
In this he said, “Therefore Come out from among them And be separate, says the Lord.” 2 Corinthians 6:17
Certainly, the follower of Christ must separate himself from the character, action, and speech of the world.

The avoidance of wine is an instruction for a sober mind, that is, clear, rational thinking and a serious mind.
Titus 2:11-12 For the grace of God that brings salvation has appeared to all men, teaching us that, denying ungodliness and worldly lusts, we should live soberly, righteously, and godly in the present age.

The shaving of the head and then letting the hair grow without cutting it again is symbolic of a new start – a new beginning.
Jesus told Nicodemus, “Most assuredly, I say to you, unless one is born again, he cannot see the kingdom of God.” John 3:3
This new beginning is a necessity to become a Christian.

Finally, a Nazarite avoided dead bodies. How does this apply to a Christian of today? I’m sure God does not want you to avoid the funeral of a loved one or close friend.
Instead, God wants you to avoid death.
Jesus said, “I have come that they may have life, and that they may have it more abundantly.” John 10:10
He said, “I am the way, the truth, and the life.” John 14:6
It is said of Him in John 1:4 In Him was life, and the life was the light of men.
Jesus is life, not death!
A Christian needs to avoid death in what he/she says, in action, and in thought.
Let your life reflect His life.