Several Ann Arbor businesses are marking major milestones this year, and if there’s a common theme to what the proprietors credit for their longevity, it’s this: Customer service is key.

So is anticipating what’s next in technology and market trends. And keeping employees happy and engaged is also important, the owners of four longtime local businesses said.

Looking ahead and anticipating changes in technology helps a business "(stay alive) as long as I have,” said Nick Arhangelos, founder of Kolossos Printing Inc., which is celebrating its 40th anniversary.

It’s hard to imagine many industries that have been more affected by technological upheaval than printing and copying.

The business that Arhangelos started in his Ann Arbor basement with an offset press, darkroom and paper cutter has mostly gone digital, with orders often now coming in over the Web.

Demand for printed college course packs, once a stock-in-trade of many local print shops, has disappeared, though Kolossos still gets work doing small-run book re-prints and dissertations from graduate students. It keeps older equipment on hand for the occasional jobs that require scoring, perforation or foil stamping.

But most of the profits get re-invested in new equipment, said Arhangelos, now 67. Over the years, that’s meant buying color laser copiers, wide-format copiers and high-speed digital color reproduction machines. The business also has diversified into shipping and digital photo developing, and it rented a storefront years ago on East Liberty after customers complained that Kolossos was abandoning the downtown.

“We’ve been through two or three recessions. We’ve survived all of those,” Arhangelos said. “This is a big one, but we’re pretty confident that we’ll survive this one, too.”

Koch & White Heating and Cooling launched 75 years ago as Koch Heating and White Refrigeration, two separate businesses that merged in 1972, president Randy Breier said. Its former respective owners, William Stoll and William Moosbrugger, moved the company to its present location on West Liberty in 1980.

Many of the company’s 34 employees originally hired on in the 1970s and ‘80s. Breier, who joined the company in 1983, said Moosbrugger, who died last year, oversaw the company’s books. He described him as a “tough” but “very fair” manager who always kept on top of his business.

“I tried to emulate Bill Moosbrugger ... not so much ruling with an iron fist or anything, but keeping the employees informed. We have weekly meetings with the management staff,” Breier said.

The recession has eaten into profits, but revenues have been sufficient to avoid any layoffs. The company’s formula for success is simple: do what you tell the customer you’re going to do and when you tell them you’re going to do it.

“We do a lot of maintenance and service contacts with local customers here that I think has helped immensely with customers purchasing things in the future,” Breier said.

September marks 30 years in business for Arbor Farms Market, which will celebrate the milestone with a sale and top-secret “special event” Sept. 30-Oct. 1. The purveyor of specialty produce, meats, cheeses and prepared foods expanded into a former Farmer Jack in 2004.

“We’ve always been locally owned and we’ve always tried to introduce local products,” said Leo Fox, the 60-year-old founder and co-owner. “It’s kind of a buzz thing now, but we’ve always done that. Over the years, we’ve had a lot of support from our regular shoppers.”

It's needed that to weather the recession and competition from much larger chains, like Whole Foods Market and Plum Market, each of which has opened up gleaming grocery stores in recent years. Fox recalls when Whole Foods was opening its first Ann Arbor store during the 1990s.

“It had me really worried,” he said.

“I think when they opened the original store, we lost some of our guests who used to come from the east side. But I tried at the time to try to build up my associates’ enthusiasm and try even harder to take care of our customers, and we did OK.”

The new store expanded the store’s deli, kitchen area and wine selection. Revenue has ballooned, but so have payroll and rent.

“I think we’re serving the community way better at the new store, and that’s what it’s all about,” Fox said.

Here’s how John Metzger, 53, explains how the German restaurant his immigrant grandparents opened in 1928 has survived so long: “It’s just good food, friendly staff. A lot of our staff has been here a long time, consistent. People like to see the same people when they come in and have dinner. We have a lot of regular… customers who have come in for years and years.”

Metzger’s culminated its year-long 80th anniversary celebration last Dec. 8, with 80-percent discounts on dinners and live music. Over the years, the eatery has added salads, fresh seafood and lighter fare to reflect changing customer tastes, and it’s begun offering beer tastings and mug-club programs to attract younger clientele.

Offering specials such as two-for-one coupons, “recession buster” specials and other special events has helped mitigate the impact of the bad economy, said Metzger, who began washing glasses at the restaurant at age 10.

“You just have to do things to get people to come in,” he said.

Contact Sven Gustafson by email or  follow him at www.twitter.com/sveng.