It's not unhealthy to eat leftovers as long as the leftovers are still good and have not spoiled.
Most leftovers are good after 5 days.
Some leftovers are good after 3 to 5 days in the fridge and some leftovers may spoil if kept longer than a few days in the fridge.
if the leftovers are frozen then they will be good after 5 days and longer.
Leftovers are okay to eat after 7 days as long as they have been stored properly.
Some leftovers are good in the fridge for only 3 to 4 days while some leftovers are good in the fridge for up to 7 days.
If the leftovers have meat or are meat then they will usually last for 3 to 5 days in the fridge but when frozen they will last for a year or longer.
If the leftovers have no bad smell or taste or the leftovers have no mold or other indicator that they are bad then they are okay to eat.
As a general guideline.
Leftovers can be kept for three to four days in the refrigerator.
Be sure to eat them within that time.
After that, the risk of food poisoning increases.
If you don't think you'll be able to eat leftovers within four days, freeze them immediately.
According to the FDA Food Code, all perishable foods that are opened or prepared should be thrown out after 7 days, maximum.
No leftovers should survive in your fridge for longer than that.
Some foods should be even be thrown away before the 7 day mark.