Yes, Alder requires a contract of at least three years. If you cancel the monitoring service during that period, you will be responsible to pay for 90 percent of the remaining balance, so it’s best to make sure that you can finish the contract before signing. Alder computes the remaining balance by multiplying the number of months remaining in your contract by your monthly rate. For example, if you have 10 more months left at $40 per month, your remaining balance is $400. If you cancel your contract, you will pay 90 percent of that, or $360.