Augustine: Daily offering of the sacrifice of the Eucharist

From St. Augustine's letter 54 (to Januarius, II.2), circa AD 400:

There are other things, however, which are different in different places and countries: e.g., some fast on Saturday, others do not; some partake daily of the body and blood of Christ, others receive it on stated days: in some places no day passes without the sacrifice being offered; in others it is only on Saturday and the Lord’s day, or it may be only on the Lord’s day. In regard to these and all other variable observances which may be met anywhere, one is at liberty to comply with them or not as he chooses; and there is no better rule for the wise and serious Christian in this matter, than to conform to the practice which he finds prevailing in the Church to which it may be his lot to come. For such a custom, if it is clearly not contrary to the faith nor to sound morality, is to be held as a thing indifferent, and ought to be observed for the sake of fellowship with those among whom we live.