Your mixed berry parfaits are best served fresh. After a while, the yogurt will start to soften the granola. However, if you do not care about the texture of your granola, you can absolutely store these parfaits in airtight containers in the fridge. They’ll keep for up to 2 days when covered with plastic wrap or sealed in a mason jar as well.  If you want to make them ahead of time without mushy granola, try omitting the bottom granola layer and add the granola at the top of the easy parfait when ready to serve.