Marketplace add on question

I wasn't sure which forum to post this in, but I'm wondering how the add on licensing model works in the marketplace. Our environment has dev, staging and production. If we purchase an add on, do we need to buy it 3 times, one for each environment?

The only public-facing site is our production site.

JohntheFish replied on at Permalink Best Answer Reply
Just once for each production site. The license includes use on dev and staging.

The mechanism for assigning licenses from your account is more than a bit clunky, so it is usually cleanest to assign the license to the live site and then copy the files to the dev and stage.