What do you do with your old Android phones or tablets? That question usually prompts three tired answers. You might trade them in for a new purchase. Or you could resell them on eBay. Probably, though, you will just stuff them in a drawer as emergency backups.
Better options exist, however, that would let you continue to get value from your aging devices. For example, you could download Google maps to create a dedicated in-car GPS navigator, or you could turn them into webcams.