Japan’s “Citizen Runner” Yuki Kawauchi is notably famous for his relentless marathon schedule. Since his humble start in February 2009 when he finished 20th at the Beppu-Oita Manichi Marathon in 2:19:26, the now 30 year-old school custodian has run 67 marathons, 22 of which have ended in victory. Twice, 2014 and 2015, he has started 12, and generally his time range has been from 2:09 to 2:18.

Kawauchi, however, is the outlier. The conventional wisdom has long held that at the very highest level professional marathoners optimized at two per year, one in the spring, one in the fall. The original cast of five Abbott World Marathon Majors was built on that assumption.

With a marathon training cycle of roughly 12 weeks, and a proper recovery requiring one month, it was felt that two per year was the way to best schedule a marathon career, with exceptions made for an Olympic or (possibly) a World Championships year, where athletes were willing to compromise their fall effort for a shot at Olympic or WC glory.

The perfect illustration of this is the current world number one marathoner Eliud Kipchoge of Kenya. Since the ’03 5000m world champion began with a win in Hamburg in April of 2013 (2:05:30), he has run two per year like clockwork, one in the spring, one in the fall, winning each and every race except his second career start in Berlin in September 2013 where he took second place (2:04:05) to Wilson Kipsang‘s then world record 2:03:23.

Even last year when Eliud won in London in April in a near-world record 2:03:05, then came back in Rio in August to claim Olympic gold, he didn’t force a fall start, saving himself instead for the mighty effort in Monza, Italy this past May in the Nike Breaking2 Project.

So, too, with rival Wilson Kipsang. His marathon career has stretched from Paris 2010 (3rd, 2:07:13) to Tokyo in late February 2017 (1st, 2:03:58). Only twice in that span has he added a third marathon, 2012 when he took bronze at the London Games, and 2015 when he DNF’d at the Beijing World Championships.

Ethiopia’s Keninisa  Bekele, too, has generally stuck to the two-per-year model since he began in Paris 2014 (1st, 2:05:04). However in 2015 he only made one start, DNF’g in Dubai in January as he worked through an injury.

But as the paydays continued to spread around the world and opportunities began to crop up where the weather was conducive to marathon running in what previously might have been off season, we have begun to see more and more athletes stretch their wings and challenge old assumptions.

With the money that now attends these newer events, and with youthful runners who might once have gone to the track ovals now running marathons in January, June, and December, the two-per-year order has evolved.

For two generations now, racing has been much more than a trophy collection exercise. It’s a business opportunity. And youthful legs like those of Ethiopia’s Lemi Berhanu Hayle, 21, carried him to the 2016 Boston Marathon title in April after taking a close second in Dubai in January and then to a 13th place at the Rio Olympic Marathon in August.

This week defending champion Keninisa Bekele was added to the BMW Berlin Marathon start list where he will go up against 2015 champ Eliud Kipchoge and 2013 winner  Wilson Kipsang in what many see as the marathon race of the decade. But it will be Bekele’s third start of the year after a Dubai-London double in the first quarter of 2017.

Recall Bekele was forced to DNF in Dubai around 20km after he was accidentally tripped at the start. He then took a close and valiant second in London to young Kenyan Daniel Kinyua 2:05:57 to 2:05:48.

But is there a price for the three per year schedule? In both 2015 and 2016 Lemi Berhanu Hayle ran three marathons. In 2015 he won in Dubai in January (2:05:28), and Warsaw in April (2:07:57), then took 15th in Beijing at the IAAF World Championships (2:17:36) in August. In 2016 he finished second in Dubai (2:04:33), won in Boston (2:12:45), then ran 13th in the Rio Olympics (2:13:29).

This year he started the year winning in Xiamen, China in early January (2:08:27), then DNF’d in Boston, making it three straight years he raced both in January and April. This week (August 30th) NYRR announced that Hayle would compete in his third marathon of 2017 in New York City November 5th.

So much of life is tied into accepted wisdom that sometimes it is hard to break out of the mind’s confinement. Maybe the old “two-per-year” saw still holds true, and Berlin’s outcome on September 24th should be instructive.

Bekele will be starting his third marathon of 2017, Kipchoge will be coming off his 2:00:25 exhibition in Monza, Italy May 6th, while Wilson Kipsang will have the most rest, returning from his 2:03:58 win in Tokyo in late February.

To date, 35 year-old Kipsang has run 17 marathons, winning 9. 32 year-old Kipchoge has run 9, won 8, while 35 year-old Keninisa Bekele has started 7, finished 5, won 2.

Older, more established stars can still pick and choose from a list of race suitors. But there seems to be enough of a financial lure to draw the young racers to more and more starting lines as hungry hearts and open wallets bounce back quicker.

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