conserve

noun

1
preserve with sugar
Mom always conserved the strawberries we grew in the backyard
2
use cautiously and frugally
I try to economize my spare time
conserve your energy for the ascent to the summit
3
keep in safety and protect from harm, decay, loss, or destruction
We preserve these archeological findings
The old lady could not keep up the building
4
keep constant through physical or chemical reactions or evolutionary change
Energy is conserved in this process

Also useful for “conserve”:Scrabble— High-value letters — see what it scores