Not considering Vigils, Saturdays or Great Feasts, what are the determining factors of serving a Great Vespers as opposed to a Daily Vespers? Is it anchored on the factor of there being a Doxastikon for the celebrated Saint? It has been our parish's common practice to simply serve Great Vespers if we celebrate a Liturgy the following day, and Daily Vespers if we don't, but it doesn't seem like the services in the Menaion care whether or not the parish chooses to serve a Liturgy. If a parish served Liturgy every day of the week, wouldn't that mean that every Vespers prior would be a Great Vespers? What if there is no Doxastikon for the Saint? I am most likely assuming incorrectly, but I have a feeling that the simple 'Liturgy? Great. No Liturgy? Daily' rule is based on common American practice of not serving many weekday liturgies unless it was a larger feast that would inherently have a Doxastikon.
Thanks for any assistance.