Question

Are battery-saving apps really efficient?

Answer 1

I have tried a fe so called " Battery Saving Apps" and have yet to find one that actually helps. Your best option is to limit apps back ground refresh, when your email pushes your emails to you, screen brightness, turn off wifi when not in use. Hope this helps

Answer 2

No, didn't help at all personal experience.  There are a lot of apps claiming they work but both for my smartphone and tablet nothing works.