If you are not married and not working far from home, there is no reason to live anywhere but at home with mom and dad, no matter how old you are. The reasons are simple and beneficial.
1. Obedience to God’s word: Always a good thing!
“For this reason a man will leave his father and mother and be united to his wife…” Ephesians 5: 31
A man can leave his parents before finding a wife if he has to work far from home, which in turn prepares him to later afford a family of his own. Jacob did that.
“Then Jacob went on his way and came to the land of the people of the east.” Genesis 29:1
There Jacob worked for 7 years to finally be able to marry his first wife, and toiled for another 7 to get the second one. See Can a Man have Many Wives?
2. Save money: Always a good thing!
The propaganda, especially in the US, is that if you’re living with mom and dad you are a loser. The idea is to guilt-trap you into moving out of your parents’ house and renting or buying real estate you can’t afford, so you can enrich property developers.
Imagine how much money you could put aside if while working you were living at home. You could share some of the expenditures with your parents, and thus avoid all the expenses associated with renting and buying something you can scarcely afford.
That way you can build your savings and have a nest egg to fall back on when a true need arises to finally own or rent a property – for example, when it’s time to get married, or when your parents die and your siblings want to sell the house to get their share of the property, or when you have to move out of state/country for a new job.
So don’t fall for the propaganda. Be smarter than that.