Completely necessary for successful embroidery.
Totally tempting to leave your fabric
on the hoop throughout the project.
Not a good idea.
The hoop, by design, stretches your fabric smooth.
The longer your fabric is in the hoop
the more it wants to stay stretched.
The risk is your fabric will not
be able to be smooth again.
Why risk it.
You are spending time and effort on something to keep forever.
Just take it off the hoop each time you put it away.
I've learned this lesson the hard way.