The Son of God lived a perfect example of the simple life.
Paul also seems to heartily agree.
"...aspire to lead a quiet life, to mind your own business, and to work with your own hands..." 1 Thessalonians 4:11
Excess is rarely a good thing.
"And He said to them, “Take nothing for the journey, neither staffs nor bag nor bread nor money; and do not have two tunics apiece."" - Luke 9:3
Again, depend wholly on the Lord.
"And Jesus said to him, "Foxes have holes and birds of the air have nests, but the Son of Man has nowhere to lay His head."" - Luke 9:58
Possessions can take control, don't let them.
"And He said to them, “Take heed and beware of covetousness, for one’s life does not consist in the abundance of the things he possesses.”" - Luke 12:15
Finally and ultimately, why the simple life?
"For where your treasure is, there your heart will be also." - Luke 12:34