With plummeting temperatures and rising heating bills, it’s no surprise we’re turning to tools like electric blankets to help us stay warm for less. But they too also have a number of guidelines to help you use them safely and properly.

According to the London Fire Brigade, you should always unplug blankets before you get into bed, unless they have a thermostat control for safe all-night use. Be sure to store electric blankets flat, rolled up or loosely folded to prevent damaging the internal wiring, and never use it when it’s wet (or switch it on to dry it.) You should also never use an electric blanket if you have an airflow pressure relief mattress or use emollient creams for conditions like eczema or psoriasis. Ask for non-flammable alternatives instead.

Most importantly, you should check it regularly for wear and tear and replace it at least every 10 years.

Do you know how old your hot water bottle is? It might be time to check