Even when drinking alone, there are often rituals. It's the same in spirit for everyone, but the specifics are individual. For me it plays a lot like in a certain song: waiting for the water to heat up without boiling, thinking about life, often watching the sunrise or recalling some dream.
Perhaps that's why the Druze would stick with the custom, too. I think that they "get" it - it isn't just "drinking", it's also the introspection that comes with it.
There are also plenty local differences. For example, the grandpa in the pic has a coconut-shaped gourd, fairly common there in Uruguay; here in Paraná (1000~1500km up north), in Santa Catarina and in Rio Grande, gourds typically have a large lip, like mine:
The ones that I saw the most in Argentina are from a third style, kind of a middle ground between my gourd and that grandpa's gourd.Then to the West (Paraguay, Mato Grosso do Sul, and even a chunk of Paraná) you'll often see people using cow horns for tereré.
What you drink might also change depending on the place. Even among hot mate drinkers; for example the further south you go, the more roasted is the yerba. It can be also coarse or almost like a flour in texture.