1)All Jewish adult males must do whatever is in their power to ensure that they daven all 3 Tefilos (Shacharis, Mincha and Maariv) each day with a Minyan.

 

This obligation is a "Chiyuv Gamur- full fledged mandatory obligation", and not just a good Minhag or Chumrah (Stringency). (See Igros Moshe Orach Chaim Vol. 2 Siman 27 and Vol. 3 Siman 7)

 

2) When one davens with a Minyan, his Tefilos are not as scrutinized by Hashem for lack of Kavanah etc. as they are when one davens alone. Therefore, one who usually doesn’t daven with the proper Kavanah, has an additional reason to try and make sure to daven only with a minyan.

 

Halachos For Shabbos Kodesh

 

1) The Yesod V’Shoresh H’Avodah, as well as many Poskim would often caution people who worked in stores (and the same goes for office workers, and anyone else that is working in the afternoons/evenings, when finding the time to daven with a minyan is difficult and often bothersome) to be extremely vigilant in ensuring they davened Mincha and Maariv with a Minyan.

 

2) One should avoid going away (e.g. on vacation etc.) to any place that doesn’t have a Minyan, unless it is absolutely necessary to go there for health reasons, livelihood (Parnasah) reasons, or for the sake of a Mitzvah.

 

A competent Rav should be consulted before traveling to a place that doesn’t have a Minyan. (Most places today do in fact have Minyanim within a short distance, and with a little research these Minyanim can be found)