I put on my tallit and my tefillin for Shacharit on each appropriate weekday morning. But I do not wear them when I go back to shul to daven mincha. It is still day, so there would be no issue of night-time not being proper for tzitzit and I would be in the proper frame of mind to wear tefillin (the notes in the Artscroll say that the commandment to wear tefillin aren't limited to morning prayers -- in fact, many sages wore them throughout the day, but we do not because we lack the purity of body and thought -- but I have these during prayer, apparently).
The chazzan wears his tallit during mincha but I do not (though I still have my tallit katan on). Why would I not wear it in the same way that I would for Shacharit? IIRC, I wear it for mincha on Yom Kippur.
Are there any groups which make it a consistent practice to don the tallit and tefillin during a weekday mincha (having already done so in Shacharit)?