If you spared something, you didn't use it or hurt it when you could have.
When you spare something, it can make people think of kindness or mercy.
Examples:
She spared some food for later.
He spared the little bird from the cat.
The kind man spared the bug from being squished.
I spared some time to help my friend.
The superhero spared the city from the bad guys.
The king spared the mouse from being eaten by the cat.