Factories will also rust rapidly in the minecraft environment where they lose 100% of their health over a 100 day period (based on the minecraft tick). Once a factory reaches 0% health either through use or decay, it is destroyed forever. To prevent this you need to regularly repair your factory through its repair recipe. To repair a factory to 100% health you need to pay 33% of its initial cost. Keeping factories around is expensive and not for the faint of heart!
Following this outline