IMO, if you are printing PLA, it’s not worth it.

The usefulness increases with the temperature. It dramatically reduced my printer’s consumption when the bed is 95°C, and allowed it to heat up to 115°C (I didn’t try anything further).

I have an adhesive insulator from Aliexpress. It has lasted for a few months without any visible wear, but I can’t say much about its longevity. But given the price, I would be kinda ok with it lasting only a couple of years.