In the past year, he believes, that has fallen to two tangi a month for the three marae at Ohinemutu.
He remembers a stretch where there were 11 tangi in a row, virtually back to back. Those days are long gone - now three or four would be "hard yakka".
"I think it's really dropped off. Whether families can afford it, they seem to be keeping them at home now.
"We get accused of being too expensive. Everyone who works in the kitchen does it voluntarily."
It's a situation, Mr Reti says, which reveals a lack of understanding about the practice of koha, under which many contribute to the cost of hosting over three days.
He envies his Ngati Pikiao cousins at the other end of the lake, who he believes have maintained koha practices more successfully.
Professor Tapsell said keeping bodies at home never happened when he was a boy.
Any talk of it and kaumatua were down to the home in a "flash" with young people to help them carry the deceased to the marae.
Now bodies don't make it back from Australia, let alone a couple of kilometres down the road, he said.
"Without the death ritual of tangihanga we're losing the real reason of why we have marae. It's about linking the dead with the living [and] with those yet to be born.
"It gives expression and context and frames our whakapapa [descent] as Maori, which is accountable back to a landscape in which our ancestors are buried.
"If we do not farewell our dead on their ancestral marae, there goes the last bastion of being Maori," he said.
A loss of connection to the institution through migration, not knowing who the people are at the marae, not feeling comfortable because of those factors and a loss of spirituality are some of the reasons he believes people are choosing to forgo mourning rituals.
Kaumatua Pihopa Kingi was wary of Professor Tapsell's position.
In his experience at Ohinemutu, he said, Ngati Whakaue dead, with few exceptions, returned there. The situation might be different in Maketu.
Families from Ngati Porou and Ngati Kahungunu who had lived in Te Arawa's [Bay of Plenty] territory for generations might elect to keep their dead in the region. There was nothing inherently wrong with that.
"I think the families concerned have a right to decide where they want to take their mate [dead]."
Professor Tapsell is developing maorimaps.com, a website which aims to help those in search of their marae. It's about engaging people while they're still alive, he said.
The uniqueness of marae should not be underestimated, he believes. Developed over thousands of years, it was something we should treasure.
"The question is, how do we get the heart back into better health, how do we start to exercise our marae so they are socially, politically and economically important to our future?" Professor Tapsell asked.
"We just bring you to the gate. The idea then is to encourage descendants to go out and ... make themselves known to the haukainga [home people]."