Answer :
The helots did all the menial work,in particular everything associated with agricultural production - which the Spartans needed for their food supply.
Without control of the helots,the Spartans would have had to do their own farming or starve,and thus wouldn't have had the time to train as full time soldiers,so they would have had no military power.
Without control of the helots,the Spartans would have had to do their own farming or starve,and thus wouldn't have had the time to train as full time soldiers,so they would have had no military power.
