Heated gloves can be worth buying for people who spend a lot of time outdoors in cold weather, or for those with medical conditions that cause sensitivity to cold temperatures. They can help keep hands warm and comfortable, and can be especially useful for outdoor activities such as skiing, snowboarding, or hunting. However, they can be expensive and may not be necessary for everyone.

Wearing heated gloves is generally safe, but it is important to use them properly and follow the manufacturer's instructions carefully. Overheating can lead to burns or other injuries, so it's important to choose gloves with adjustable heat settings and avoid leaving them on for too long. Some heated gloves are also designed to automatically turn off after a certain period of time or if they become too hot.

It is not necessary to wear glove liners with heated gloves, as they are designed to provide warmth on their own. However, some people may prefer to wear glove liners underneath their heated gloves for added warmth and comfort. This can be especially useful for people with very cold hands or those who spend a lot of time in extremely cold temperatures.

The level of warmth provided by heated gloves can vary depending on the specific model and brand. Generally, heated gloves can reach temperatures of up to 150 degrees Fahrenheit, but most models have adjustable heat settings that allow the wearer to choose their preferred temperature level. It's important to follow the manufacturer's instructions and safety precautions when using heated gloves to prevent burns or other injuries.