Peter and Elizabeth Bosshard finally realised they had become bona fide art collectors when they ran out of space to display their assorted paintings and sculptures.
Over the past 40 years the couple have amassed 5,000 items dating from the 1970s to today, making theirs the biggest private collection of contemporary Swiss art.
What began as a hobby quickly grew into a serious sideline to their respective day jobs in law and biology.
They began by buying art from around the world but soon decided to concentrate all their spending power on one area - up and coming Swiss artists.
"At first we didn't know that this would become a collection," said Peter Bosshard.
"In the mid 1980s we realised that the office wasn't big enough to store it so we decided to rent some space to have a better view of the pieces."
They found a room in an old factory and started inviting friends to see the works, before moving into holding invitation-only public viewings.
By the 1990s parts of the collection were going on show in museums and galleries around Switzerland and Germany.
It was only a matter of time before the Bosshards decided to go public with their collection by opening a new museum in the scenic town of Rapperswil-Jona on the shores of Lake Zurich.
"In the past few years we thought about giving it all to a foundation. An alternative would have been to give parts or the whole collection to one of the existing museums, but they only wanted to have one piece or pieces, or one artist they were particularly interested in," said Peter Bosshard.
"Pretty soon we knew that we wanted to have the whole collection and the whole range together."
Instead, all of the items were donated to the Kunst(Zeug)House Rapperswil-Jona foundation which was set up in December 2006 to look after and exhibit the collection.
A museum design contest was held and building work started on the winning plans by architects Steumm Wolf to rework an old army storehouse in Rapperswil-Jona.
Over half of the funding for the SFr8 million ($7 million) project was contributed by the cantonal and town authorities.
The collection is so large that most of it has to remain in storage, to be brought out and exhibited in rotation. The museum opened recently with a first sampling of paintings, drawings, sculptures, photographs and videos - a glimpse of the range of work by Swiss artists over the past four decades.
"It's a very prominent and good collection of Swiss art of all different kinds and very different styles and very different media," Bosshard commented.
"In the first few years we also collected internationally well-known artists but in 1975 we decided we only wanted Swiss artists.
"Swiss art has produced such an enormous variety of all kinds of artwork that we didn't think that this was a narrowing that would restrict our collection. Like good international art, Swiss art has high standards."
Hotline to galleries
One exception to the Swiss-centric collection is the museum's Robinson Crusoe library, a reading room that contains more than 4,500 books and paraphernalia linked to the famous tale, the writer Daniel Defoe and similar themed stories.
"Whenever I am in New York I go to see my antique bookseller and they send me offers to buy. I also have booksellers in London, Antwerp, Paris, Milan, Geneva and Bern who send me offers," Bosshard explained.
"But I always like to go there and touch the books. That's one of my biggest joys, besides collecting art."
The Bosshards worked with top galleries in Switzerland to build up their collection, picking major Swiss artists such as Uwe Wittwer, Hugo Suter and Rolf Wineervierese.
"They tell me, 'You should see this young artist, he seems to have very big potential'. Then I go and look at the exhibitions in galleries and I think if this is an artist I would like to have in the collection.
"Another particularly of my collection is that I stick to an artist that I have chosen. I continue to follow them in their work and buy pieces every time they exhibit them.
"A cross-country skier is someone with long stamina to go on and that's what I call an artist who makes good art over 30-40 years."
The Bosshards themselves expect to continue with their decades-long involvement in the arts until they are "too old or too tired", and through the foundation will continue to be a part of the collection's future.
"I hope that this Kunst(Zeug)Haus grows into a place of contemporary Swiss art," Bosshard added.
"I also hope that the artists in my collection grow with this institution and get better known in Europe and internationally and that this Kunst(Zeug)Haus remains a place of good art."
swissinfo, Jessica Dacey in Rapperswil-Jona
The Bosshard collection
The Kunst(Zeug)Haus plans to show the Bosshard collection on a rotation basis by changing around the main exhibition every several months.
The museum also has a temporary exhibition room that will feature works by one of the major artists in the collection.
The entire collection of more than 5,000 works includes sculptures, paintings, drawings, photographs and videos. The museum is also home to the Bosshards' Robinson Crusoe library, which has more than 4,500 books, comics, drawings and objects related to the book or the author Daniel Defoe. It is open to museum visitors.
An education programme runs simultaneously, allowing children to view the works and then try to recreate things they have seen in an adjacent art block.
Canton St Gallen contributed SFr4.2 million towards the creation of the SFr8 million cost of the museum, Rapperswil-Jona municipality gave SFr1 million, and the rest was given by the Bosshards, the foundation and sponsors.