As an entrepreneur, you probably love shiny new things, but make sure you don’t ignore your cash cows.

There’s an artist in southern France named Gerard Isirdi who paints simple scenes of life in a small French village. One of his pictures shows an old Citroen parked outside a café; another is a scene of a village square on market day.

Isirdi’s most famous work is a painting called “Homme au journal,” literally translated as “man with newspaper.” The subject is a man sitting tucked underneath a wide-brimmed hat with a glass of pastis by his side as he buries his head in the La Provence newspaper.

Tourists from all over the world flock to Isirdi’s studio in the touristy village of Lourmarin to buy their copy of “Homme au journal” as a souvenir of their vacation in the south of France.

My wife and I went to Isirdi’s shop last month to buy an “Homme au journal” print but, much to our disappointment, they had run out. The large prints sell for €55 (about $75 USD) and they probably cost Isirdi around $5 to make. Can you imagine having a world famous, self-marketing product that you could sell for $75 and manufacture for $5? Wouldn’t you make sure you had enough stock of that little cash cow?

Isirdi has painted hundreds of scenes, but this one picture is a blockbusting winner. Yet people travelling from miles away can’t buy it because someone forgot to call the printer that day.

The current design of the Volvo station wagon has been around for decades. If you step inside a 2013 XC70, it looks virtually identical to the 2005 model. It has the same steering wheel, seats, engine, and dashboard. If it weren’t for the new car smell, you could hardly tell the difference from the driver’s seat. The folks at Volvo know that their stodgy station wagon isn’t winning any innovation awards, and that it gulps gas and it’s out of step with the latest car designs. But they haven’t ignored their bread and butter. To a safety-conscious soccer mom or dad, the Volvo XC 70 is the perfect car, and the guys on the line can crank out an XC 70 with their eyes closed, so what would be the point in changing it?

Monopoly is the quintessential board game, and the folks at Parker Brothers (a subsidiary of Hasbro) have nurtured that single idea since the 1930’s. Even though Parker Brothers has published more than 1,000 games, it is Monopoly that is their blockbuster, and they squeeze that lemon for all it is worth. My kids just discovered Monopoly, and that’s three decades after I fell in love with the same game. You can get a local edition of Monopoly everywhere from Paraguay to Poland.

Heineken, Lego, Chanel No. 5, the 737, Oreo Cookies, and Star Wars are some of my favorite examples of the gift that keeps on giving. The owners of these products have the common sense to hang on to what they’ve got, and nurture and support their winners long after they have become bored with their invention.

As entrepreneurs, we love chasing shiny new balls, but sometimes it is your (cash) cows that need a hug.