Cooked Sweet Potatoes will last for about 3 to 4 days in the refrigerator.
After 4 days the cooked sweet potatoes will start going bad and should be thrown out.
When refrigerating cooked sweet potatoes you should put them in a shallow container or in Ziploc bags and then use them within 4 days of refrigerating them.
If you want to keep the cooked sweet potatoes longer you can freeze them in freezer bags or other freezer safe container.
When frozen the cooked sweet potatoes will last up to a year.
Although it's best to use the frozen sweet potatoes within 6 months of freezing them because they start losing the fresh taste and the texture of the sweet potatoes change as well.
Sweet potatoes whether cooked or raw are best eaten as fresh as possible.