Old pavers can become stepping stones, pot stands, wildlife features, and even a cool resting place for pets. Reusing them saves money, reduces waste, and gives a backyard the sort of settled character that new materials spend years attempting to acquire.
Before beginning, scrub each slab (you might need a stiff-bristled scrubbing brush, like this from Amazon), inspect it closely, and reserve only the sturdy ones for any garden idea that is weight-bearing or underfoot. You should also be aware of those with crumbling concrete, sharp edges, or old chemical stains. Though, a paver with a hairline crack may still be charming in a planted corner.