They stand like sentries on the sidewalks of Brickell Avenue and Biscayne Boulevard, along Flagler and Eighth streets, about 100 of them — yet they are barely noticed and rarely used.

The question: What to do with the archaic, bland pay phones that once served an extraordinary public service but, at a time when just about everyone has a cell phone, seem little more than space-eating advertising sites cluttering Miami sidewalks?

“I suppose you can justify one without an ad every 12 blocks or so,” said Peter Ehrlich, a Scenic Miami member whose group considers outdoor advertising to be visual pollution. “They’re not really pay phones anymore, it’s visual clutter, an eyesore.”

Though most everyone agrees pay phones are so rarely used they don’t pay for themselves and would disappear without the advertising, they still serve an important function, advocates argue.

“Miami has a large number of tourists, especially foreign tourists whose cell phones won’t work,” said Bruce Renard, executive director of the Florida Public Telephone Association. “And it still serves a major public purpose. When the towers went down in New York the pay phones were the only phones that worked for weeks.”

Stroll down most of Miami’s main streets and every few blocks you’ll see a 5-foot tall, three-sided structure with a couple of sides of advertising, usually for bottled water or a clothing line. The old metallic phones inside the small booths have stickers showing a call is now 50 cents.

The public’s view on what to do with pay phones? Keep them, at least according to a very unofficial poll of The Miami Herald’s Public Insight Network.

Romy Casablancas, a local attorney, said they’re not hurting anybody.

“You would not believe how many times I’ve had to use them, and I have a cell phone,” she said. “They are necessary. In Europe they are everywhere. I don’t see why we should not have them here. They come in handy many times.”

Homestead’s Gwendolyn Ross, who still thinks pay phones cost 25 cents a call, said “most emphatically yes” to keeping them around. “A pay phone is one of those things that people don’t think they need until they need one. Ask the survivors of recent disasters.”

The slight opposition came from Miami Beach’s Charles Urstadt, who thought a phone call cost 75 cents.

“The less visual clutter and physical obstacles pedestrians have to contend with, the better Miami-Dade will be,” he said.

Countywide, advertising on pay phones isn't a hot-button issue, at least for now. Deputy Miami-Dade mayor Chip Iglesias said the county has contracts for the airport and its jails — the only pay phones in town he believes pay for themselves.

In Miami, the pay phone issue first surfaced in Miami about a year ago, when a group of people from the city’s Upper Eastside complained to Miami Commissioner Marc Sarnoff that new pay phones were being erected on street corners. It turned out they weren’t new, they were just getting a face-lift with cleaner advertising panels.

Sarnoff had his staff do an audit, and the results didn’t surprise him: In 2012, each of the 96 pay phones on city right-of-ways in Miami averaged 200 calls a year — about one every other day. Free calls to 911 averaged less than one a week from each phone. To put up a phone on a city right-of-way you must obtain a permit from the city. The same goes for placing an ad on a phone booth.