Once a week would be a good start. Like practicing jews do.

Yeah, I don't like these gestures that are tied to a specific day. It's blue tribe signaling with no real sacrifice necessary.

I believe the "minimalism" movement has been far more impactful in the long-run despite fewer adoptees, just by being a trend that capitalized on the benefits in its messaging. Those who optimize for minimalism consume less, but constantly.

There are worse things, like switching off light and not using appliances for an "Earth hour", while making the power grid shedding the excess capacity frantically.

If you want to make a difference, do something small, but do it every day.