I grew up with custom of Chabad style tefillin in Chabad family, and I later went off the derech for a few years and stopped wearing tefillin; I became engaged (and later married) and my wife bought me a pair of tefillin but it was not Chabad style. My question is if I should go back to my family minhag and continue putting on my original tefillin or just continue with the tefillin I started wearing for past few years now? (I lately felt like I should go back to continuing my family minhag style tefillin, but I wasn’t sure how to proceed Halachically)
It is better to keep to your family minhag, however since you didn’t use those teffilin in a long time, they should be taken to someone to be checked, to make sure that the parshiot and the batim (inside and outside) are alright and that they didn’t get ruined over the years. Until then use your new pair.