It takes a period of every 5 years until every atom in your body is replaced.
Every 5 years there is a complete, 100 percent turnover of atoms in the body.
Your skin replaces itself by a process of shedding the skin while new skin is growing underneath the skin.
Skin renewal process and skin renewal is basically exfoliation (shedding) of the skin.
Your skin cells regenerate themselves every 27 days and skin cells are constantly dying and replacing themselves even without you realizing it.
Your skin does change significantly every 7 years or so but actually your skin is changing all the time and much sooner than every 7 years.
Your skin cells live about two or three weeks before they are replaced with new skin cells.
The human body does replace itself every 7 to 10 years.
Although it's not in the way that some people may think.
For example you're not actually getting a new body every 7 years or so but instead your cells in your body are reproducing and replacing themselves and rebuilding themselves every 7 years or so.
You'll usually notice significant changes in your bodies appearance such as in your face as your face change every 7 to 10 years.
So you may look different 7 years from now.
Your face changes much more quickly from the time you're born and until you turn 18 and then the body changes at a slower rate.
When you're an infant and then reach 1 year old to 2 years old you'll notice a huge change in your faces appearance as well as you've grown a lot in those years.
Your body and face are constantly changing over the years without you even realizing it.
Your bodies cells do reproduce at a nonstop rate, but you're not a new person every 7 years especially after you turn 18.
You still have the same body but your facial features can change and your body can still grow out wider.
New cells in the body are being replaced all the time and over a few years you'll have some new cells in your body as they replace themselves and repair themselves.
You should certainly notice a change in your appearance though every 7 years to 10 years.
However it's the same body but your body does change over the years and so you'll look like a new person every 7 years to 10 years.