Maybe you’re considering getting another conversion. But what about the mezuzahs you already have on your doors? In your new community (even if it’s within the same geographic area), you are not (or “might not” be) halachically a Jew. Mezuzot on your doors could confuse people, and technically, you aren’t obligated in the mitzvah.
Of course, you can take them down and then put them back up after your next conversion is over.
But maybe you don’t have to. As I mentioned previously, I’m unusually attached to my mezuzot. It was important to me that I could continue to leave them up. So I asked, and I made sure to tell the rabbi that this was important to me. And I was told that I could leave mine up.
I don’t suggest asking your congregational rabbi. Ask your beit din rabbi. If you don’t have a beit din, wait and ask when you do. (Of course, opinions may differ here.) Congregational rabbis overwhelmingly don’t know how halacha applies to conversion candidates and doubtful Jews. The beit din deals with these questions all the time, and they have come to an halachic ruling on the matter. Your community rabbi may have never heard the question before, and if he gives an immediate answer, then you know he has not checked the sources or called a more knowledgeable rabbi. It is unlikely that he knows the answer off the top of his head, and some rabbis, for good or for bad, just want to give an easy answer and move on. He may even believe it is an honest ruling. “Of course non-Jews can’t do X!” is not always the right answer. The answer is almost always more complicated, even if it comes to the same conclusion.
The lesson of the story? Ask and you might just receive. But know who to ask and how to ask.
From my off hand knowledge, as far as I know the only Mizva that a non -Jew may not preform is keeping Shabbat in its entirety. Shabbat is defined as an "Ot' a covenant , set apart for Jews. I wouldn't be surprised if the applies for Tfillin too, its defined as an Ot. But what's the problem if a non Jew puts a Mezuza on his door, or lights Shabbat candles, or shakes a Lulav.
After q quick google search apparently there is halachic apprehension from a non Jew affixing a Mezuza.
I am guessing – a wild guess here. that Tfillin and Mezuza are so similar in some respects that prohibition was applied to both cases, but I'm not yet convinced that they should equated.
@Menash:
Tefillin seems to be an interesting case; I'm not sure of the reasons for the various opinions but having spoken with people who've converted in different cities, I've heard of three different practices!
1. No wrapping tefillin until you get out of the mikveh. Basically you get out, get dressed, and immediately your Rabbi helps you put on tallit and tefillin (my Rabbi was Sephardi so your mileage may vary on the tallit part). This is what I experienced.
2. You begin wrapping tefillin boxes without the parchment inside a couple months before going to mikveh.
3. You begin wrapping regular tefillin several months before mikveh.
I"d be curious to learn the reasoning behind these opinions,or if anyone has had a different experience.