am not sure if this is still a thing or not, but it was my understanding that a Catholic Priest was restricted to the number of Masses he could celebrate per day; which explains employing pre-consecrated elements.
In Roman Catholicism some priests have permission to say up to four masses per day, but all are required to say at least one. In Orthodoxy a requirement to serve the Divine Liturgy does not exist except insofar as pastorally required, so for example, retired priests aren’t serving private liturgies (which are forbidden) although many frequently concelebrate if they are physically able - concelebration historically being prohibited in the Roman Rite with some extremely rare and unusual exceptions.
In Orthodoxy, the rule is one Eucharist per priest per altar per day. So any church which has more than one liturgy per day must have more than one altar. For this reason one occasionally sees Orthodox cathedrals that have smaller chapels attached, or multiple altars attached to one massive iconostasis. An example of the former is St. Nicholas Antiochian Orthodox Cathedral in Los Angeles, which has a smaller chapel used for a Spanish language Divine Liturgy. Also St. Ephrem’s Syrian Orthodox Church in Burbank, California, has a small chapel off the Narthex but as far as I am aware they do not use it. Two examples of the latter would be a large Russian Orthodox church in Russia, I think in St. Petersburg, the name of which I forget, which has multiple altars attached to a single iconostasis, the effect being there are multiple Royal Doors and sets of Deacon’s Doors. Also at St. Anthony’s Coptic Orthodox monastery in Yermo, California, the iconostasis has at least one side chapel next to the main altar; the doors which correspond to deacon’s doors in a Coptic parish lead to spaces where the faithful pass through the iconostasis and receive the Eucharist from the side of the altar, rather than facing it, the men using the door on the left and the women on the right, but at St. Anthony’s, the space to the left of the altar is a smaller side altar I have seen used for training newly ordained priests during supplemental liturgies, and as for what is behind the door to the right of the altar, I have no idea. That might be the basis for an interesting gameshow, actually.
One interesting side effect of this rule is what happens to the parish schedule on days where there is a Vesperal Divine Liturgy of St. Basil, such as Christmas Eve; the liturgical day ends and a new one begins at the end of the liturgy. This means on the morning of Christmas Eve there can be a Typika service, which is analogous to the Anglican service of ante-communion, although interestingly, the Typika can be said as a reader service, whereas as far as I am aware Ante-Communion in Anglicanism requires a priest (unlike Mattins and Evensong, but perhaps I am wrong;
@Jipsah or
@Shaner might know) but no Divine Liturgy. We see this again on Holy Wednesday, where the Presanctified Liturgy of St. Gregory, which is a vesperal liturgy, is served for the last time that year, usually in the morning, but this does not clash with the Vesperal Divine Liturgy on Maundy Thursday (which, like the Vesperal Divine Liturgy on Holy Saturday, or the pre-1955 Paschal Vigil Mass in the Roman Catholic Church, served in the monring), since the Presanctified Liturgy of St. Gregory is a Vesperal Liturgy. And indeed, this also explains how the Mass of the Presanctified in the Roman, Anglo-Catholic and Lutheran churches does not interfere with the Paschal Vigils, since the words used at the Mass of the Presanctified are the same as those used in the Presanctified Liturgy of St. Gregory, and both the Roman and Orthodox church attribute them to Pope St. Gregory the Great. The Orthodox Church does not serve a Presanctified Liturgy on Good Friday, but perhaps it did, or perhaps the Roman Church used to follow the one liturgy per altar per celebrant per day rule, not allowing multiple priests to celebrate successive masses on the same altar, or perhaps both are the case, since this would explain why the Presanctified Liturgy of St. Gregory is Vesperal.
This is in contrast by the way to the older Pre-sanctified liturgies, such as the Pre-sanctified liturgy of St. James, which is usually dated to the fifth century. The practice of the Presanctified Liturgy, like so much else, can be traced to the Syriac Orthodox St. Severus of Antioch, who was until recently widely regarded in the West as an anathematized monophysite heretic, which is nonsense, since he was not a monophysite, and he had a massive influence on Chalcedonian theology, particularly the areas of Christology that relate to Theopaschitism and Communicatio Idiomatum, and on liturgy, for he also wrote* the Christological hymn par excellence, Ho Monogenes “Only-Begotten Son and Immortal Word of God, Who for our salvation didst will to be incarnate of the holy Theotokos and Ever-Virgin Mary; Who without change didst become man and was crucified; Who art one of the Holy Trinity, glorified with the Father and the Holy Spirit: O Christ our God, trampling down death by death, save us!“
I am a fan of the Orthodox approach because it increases the piety surrounding the liturgy, that there can only be one of them, or perhaps two, in a twenty four hour period (if one of them is a vesperal divine liturgy).
*Some argue this hymn was written by Emperor Justinian but this notion is absurd, since the Syriac Orthodox Divine Liturgy actually opens with this hymn, and there is no Chalcedonian more reviled in the Syriac Orthodox Church than Justinian, because of his arrest and execution of most of the bishops of Antioch, with only St. Jacob bar Addai escaping, allegedly due to being warned by the emperor’s wife Theodora, who actually was Syriac Orthodox; so as to ensure the survival of the Syriac Orthodox Church St. Jacob “Baraddaeus” as he is known in the West ordained, acting sola, which is permissible in emergency circumstances, hundreds of bishops, making it impossible for Justinian to round them all up. It is for this reason that the Syriac Orthodox are sometimes called Jacobites, and not, as one ignorant of history might erroneously suppose, because the Syriac Orthodox Patriarch of Antioch was in any sense a supporter of Bonnie Prince Charlie or the pro-Stuart faction opposed to the Hannoverians.