With proper care, slimes can last for a few months or even years. However, it is normal for slimes to deflate or melt over time due to the nature of slime ingredients.
To keep your slime in the best condition, make sure to wash your hands before and after play. It is recommended to play with slime on a clean surface to prevent any debris or bacteria from getting in your slime. After play, store your slime in an airtight container and a cool environment. If your slime is sticky, re-activate using the included slime activator spray or a borax solution.