Modern life is fast paced, time consuming and full of distractions where time gets lost and activities fall through the cracks.  We are forced to make schedules and just hope that we are able to keep them.  While there is no evidence the ancient Irish held monthly ritual observances, in modern America regular ritual observance of the gods can help us maintain our relationships with them. If you are looking to build a local community of like minded worshipers monthly gatherings are a necessity.

As to when to hold the rituals there are a few options.  Using the modern 12 month solar calender would be the simplest, but gentlidecht is a faith based on the practices of the ancient Irish. There for we should be following the calender used by the ancient Irish to dictate out religious schedule.  We have two sources for a lunar calender on which to base the schedule, the Coligny
Calendar used by the Gauls and Irish Neolithic art in and around passage mounds.  Admittedly we do not know if the Iron Age invaders (Celts) of Ireland
adopted the calender inscribed by the Neolithic Irish but knowing that the
Gauls, another Iron Age Celtic people, did use a lunar calender we will continue to work on the assumption that the ancient Irish did as well.

The carvings on Kerbstone 52 at Knowth

Based on the scholarship of the available calenders the year, month and days were split into a dark half and a light half with the beginning being the dark period of each.  This would place the start of the year during the darker months (Winter), the start of the month at the astronomical new moon (dark moon) and the start of the day at sundown.  Sounds simple but scholars have spent years working out the exact calender cycle and several theories exist.

Just based on this information genti could hold their monthly gatherings on or shortly after the dark moon.  This would provide 12-13 annual opportunities for community building and worship.  Of course each group could delve into the research further and come up with more exact religious calenders as well. I prefer the notional Celtic calender created by the Time Meddler which is a 12 month lunar calender with an occasional leap month.

The point is genti (followers of gentlidecht)  need to build a community, starting at the local level.  The best way to do so is to slow down and start getting together.  Establishing a religious calender and then sticking to it will help achieve that.