What's a thing that increased your power?

Doesn't have to be a thing you bought. Just some thing you didn't have but then once you did it expanded your scope of actions.

The first obvious example that comes to mind is a car. Plenty of drawbacks to prevalence of cars, but being able to go where I want when I want, and far away, is very transformative.

I'm interested in other examples of things that aren't just useful, but that open new possibilities.