Location and TimesNumbers 4:2 From thirty years old and upward even until fifty years old, all that enter into the host, to do the work in the tabernacle of the congregation.
These men, Levites, were going to have only a 20 year window of service. The work these men of God did was back breaking. They carried, moved, set up, and took down the Tabernacle. God took care of His people. They had to be old enough to do the work and young enough to not get hurt.
I am always amazed at how God cares about the smallest details in our lives. He loves you and will do what is right by you! He will take care of you. Trust Him!