I really like having a gender-neutral pronoun, but I know that not everyone agrees on the usage. Now I use it for people that have explicitly asked to have "ri" used for them. I also use it when I don't know the gender of a person and I want to make sure that's clear.
Otherwise I'd use "ri" in feminist contexts, but I might be careful using it around people I think might be conservative.
When should or shouldn't I use "ri"?
I usually use "ri" when another person indicates it as their pronoun, when I don't know somebody's pronoun, and when I talk about a hypothetical person.
Most Esperantists, that I know, know this pronoun, so I don't hesitate to use it when talking with them. And even if I am not sure whether another person knows it, they can easily check the meaning of this word in ReVo or Wikipedia.
For almost a year now, I have been using ri as a general pronoun independent of the gender of the person, so I use it even when I know the person to be male or female. More generally, I prefer to only mention a person's gender when it's actually important (which isn't very often). And when I do mention it, I prefer not to mention it repeatedly, so I don't want to mention it every time I use a pronoun, just like I don't want to mention someone's age, skin color, native language, nationality, sexual orientation, dress style, religion or political views every time I use a pronoun.
When speaking to people that I rarely speak to and of whom I'm unsure whether they know ri, I sometimes switch to using ŝi and li, but this is becoming less and less common. I also remember one occasion last summer where I switched to ŝi and li when speaking to a conservative person, even though I was quite sure they understood ri, just to avoid that our discussion would move away from the topic we were discussing towards the topic of gender-neutral language. But I already decided that I will stick to ri the next time this situation comes up (maybe with the same person), as I don't want the views of conservative people to govern the way I speak and the way I decide to mention or not to mention certain traits of the people I speak about.
The pronoun ri may be well-understood in the young Esperanto speakers' filter bubble, but please bear in mind that in the general population of Esperanto speakers, many of them being beyond their 60ies, it is neither well-known nor accepted.
I do not accept a general ri for two reasons:
I myself have been using ĝi as general pronoun for a few years now and it feels totally natural to me.
I do, however, acknowledge, that traditional Esperanto lacks a possibility to explicitly refer to non-binary people. Whether one wants the pronouns li and ŝi to become less used or even archaic or not, it is still a kind of discrimination that there is no pronoun for the third gender. For this reason, although it still violates my second argument mentioned above, I use "ri" in order to refer to non-binary people, as there is a need for that and no traditional means. I can argue based on §8 of the Preface to the Fundamento ("Se ia aŭtoritata centra institucio trovos, ke tiu aŭ alia vorto aŭ regulo en nia lingvo estas tro neoportuna, ĝi ne devos forigi aŭ ŝanĝi la diritan formon, sed ĝi povos proponi formon novan, kiun ĝi rekomendos uzadi paralele kun la formo malnova.") that is such a case, where the old rule (the incomplete pronominal system) is "tro neoportuna".
As with any unofficial root/affix, use with caution. I asked two native kids about "ri" and they did not understand it (they had never heard it). They feel it is a pronoun, but have no idea of what it means.
There is an Esperanto for reduced communities (for example interest groups, some families) where many experiments are made (ri, ŝli, na, iĉ ...). In a more global setting though, talking to (or writing to) other people you don't know, I'd highly recommend against "ri", "na", etc.
Why? It just hinders communication, and that kind of defeats the purpose of Esperanto. It's like willingly using your local slang with people that share your language.
Anyway, if you feel the urge to innovate, and you firmly believe in that new feature you (or somebody else) came up with, go ahead and use it, it might even be fun to try it (in our family we every now and then use "ŝli" in jest, for example). But be ready to fall back to the common "normal" international Esperanto if you want the communication to flow.
So the general answer to when you "should" use it: never. You "might" want to use it though in some situations, as explained above.
**Esperanto sube
Well, there are two classes of people. The first is the riistoj and then there's everybody else. The riistoj are those who say that it should be used in all cases where one does not know the gender of the referent or it is irrelevant. (Ri skribis leteron al sia patrino.) The rest have different views on when it should be used, some going so far as to say never.
I'm not a riisto, so I only use it when somebody requests me to use in en lieu of the traditional li and ŝi. When the gender is unknown, I use li as is customary of other languages of I speak as well as the original Esperanto; however, if the gender is irrelavent, I use oni.
Nu, estas du klasoj da homoj. La unua estas la riistoj kaj tiam estas ĉiuj aliuloj. La riistoj estas tiuj, kiuj diras, ke oni devas uzi ĝin ĉiam, kiam oni ne scias la genron de la referenco aŭ kiam ĝi ne gravas. La resto havas malsamajn vidojn pri kiam oni devas uzi ĝin, kelkaj homoj diras neniam.
Mi ne estas riisto, do mi nur uzas ĝin kiam oni demandas, ke mi uzu ĝin anstataŭ la tradiciaj li kaj ŝi. Kiam mi ne scias la genron, mi uzas li laŭtradice de aliaj lingvoj, kiujn mi parolas, tiel kiel la originala Esperanto; tamen, se la genro ne gravas, mi uzas na oni.
It's a very controversial pronoun that almost no one likes to use, besides feminists and the like. So even while most know it, very few will actually use it, really. (But it might seem to be a lot of people, as the most active online are feminists and allies.) So I'd recommend you to not to use it, unless explicitly asked for someone as their pronoun. Enjoy Esperanto!
