Is A Heated Sleeping Bag Worth It

How long does a heated sleeping bag stay warm?
This is very dependent on the size of the power bank you use. If you have a big power bank, it's possible to run a heated sleeping bag all night. This will drain your power bank, though you'll need to recharge it if you plan consecutive days of camping.

How warm do they get?
It's important to note that they don't actually get that hot! A hot water bottle, for example, radiates a lot more heat. The heat provided by a heated sleeping bag is more like a toasty warmth. Unlike a hot water bottle, though, the heat is consistent for as long as you keep it turned on, and it also covers a broader space (check the sleeping bag heat range as they all focus on different areas.

Are heated sleeping bags worth it?
In short, I'd say yes! Having the heated sleeping bag when camping definitely increased the comfort level of my night's sleep. Having said that, they do have their limitations.

Unless you go to the effort of charging your power bank each day (or taking multiple with you), then you won't be keeping the heat on all night. One of the best ways to ensure a good night's sleep is to avoid going to bed cold. Your body heat will then do the work, keeping your sleeping bag warm throughout the night. I, therefore, found the heated sleeping bag really great for turning on a bit before bed to ensure I was toasty warm before falling asleep.
If I got up in the night for a wee, I'd turn it on to have a warm bag to get into when I returned. It was also nice knowing that if I woke up cold, I could press a button and feel warmth in seconds. For cold sleepers, I'd definitely say heated sleeping bags are worth it.