DAYTON — The best companies — those out to grow and thrive — never stop improving, remaking and expanding their product lines, experts say.

But they shouldn’t blunder into change without asking customers for their opinions, either.

Wendy’s, the Dublin-based burger chain, is introducing its Dave’s Hot ‘N Juicy burger, a remake of the sandwich it has served for 42 years. The 6,600-unit restaurant chain hopes the new sandwich will put some sizzle into its sales. In six of the last 11 quarters, the company reported lower or flat revenue at restaurants open at least a year. And early next, year it will dish out a revamped chicken sandwich.

Dayton-area marketing experts said the relaunch by Wendy’s is bold, but necessary for companies fighting to gain market share. And other companies can learn from it.

“Competition is fierce,” said Irene Dickey, a lecturer of marketing at the University of Dayton. “Consumers’ needs and wants keep changing. Re-launches are necessary.”

‘New and improved’ may be a cliche, but it’s also a good business strategy, said Mike McCarthy, asssistant director of marketing at Miami University.

“The reality is, unless you are continually realigning your products and brands with what customers want, you end up creating a big piece of news like this,” McCarthy said. “Now there’s all this attention on the burger.”

But, whether fine tuning a product or giving it a complete overhaul, companies should move with caution and quiz customers about what they want. In Wendy’s case, the company polled 10,000 people about what they liked or disliked about hamburgers. Executives journeyed to countless restaurants across the country to try different burgers and the company conducted in-depth research on ingredients.

David Bowman, chief marketing strategist for the Ohlmann Group, said Wendy’s succeeded in doing its homework, an important lesson for other companies considering changes.

“Ultimately, what they did well was they asked the consumer,” Bowman said.

The volumes of customer data available to companies and the technological capabilities they have for interpreting that information have given companies powerful tools for market research, he said. The problem for many companies is having too much information rather than too little, he said.

With this latest initiative, the company needs to repeat history, said Chuck Vella, owner of Vella Inc., a Dayton-based marketing firm. When the company launched in 1969, its burgers were a “breakthrough” that differentiated it from such competitors as McDonald’s and Burger King, he said.

“I think it has to have a breakthrough product again,” he said.