On April 1, 2019 NYS residents installing new OR replacing smoke detectors are required to install either hard wired to your home OR they need to have a 10 year, sealed, non-removable battery.
You do NOT need to replace detectors currently in place. However, if you put your house on the market, or for landlords, have new tenants moving in, you must replace them with the ten year kind. Stores in NYS will not be carrying the removable battery detectors as of April 1.
Most of the 10 year detectors cost around $25 or so, and for about $40-ish you can get the one that are smoke AND carbon monoxide which is also required by the State. They should last about 10 years, or until your tenants steal them (which is the case in my life). Supposedly the “tamper-proof” sealed up detectors will prevent tenants from removing the batteries (which they usually do upon moving in). editor’s note: These detectors are NOT “tamper-proof”. I have had tenants cut those two little wires inside to disable it. I STILL have to buy more every time someone moves out due to this.