A recent study of 10,000 facilities by Glenworth Financial shows that the annual cost of assisted living averages $36,090 nationally, a 25% increase over 2004. Costs ranged from $4,921 per month in New Jersey to $1,981 per month in Arkansas. Westchester county will fall into the higher end of this spectrum. Factors such as the size of the residence, dining plans and care services will also impact each individual's overall expense.