Seventy-two-year-old Sam Leonard from Indian Rocks Beach walks about 15 miles a day.

Leonard and his longtime friend, 74-year-old Al Blake from Sarasota, are taking on the walk of a lifetime, walking coast to coast.

The men are trying to raise money for the “Walk for Rehabbing Vets” charity.

With the same mission - to help raise money for injured veterans needing rehabilitation - the men started in Indian Rocks Beach on Tuesday morning and will finish in Los Angeles.

"I want to do it for the veterans," said Blake, who served in the U.S. Marine Corps and the Army.

The men have been friends since 1970. They worked at the same law firm, were both former athletes and even ran a marathon together in the '80s.

After decades of friendship, the coast-to-coast walk will be meaningful for both men.

"I was on the Presidential Honor Guard. I was selected for that when I was in the Army,” said Blake. “I walked the Tomb of the Unknown Soldier and I was involved in 80 full-honor funerals."

Donations to support the men's efforts can be made through the donate tab on Walk for Rehabbing Vets.

"I am not a veteran,” said Leonard. “I did not participate in the war. In fact, I protested the war, and I've always had second thoughts about that, especially now that I'm older. So now this is my chance to do something in return to all those men and women who have made such huge sacrifices for our country and for me."

With about 3,000 miles to go, the men will cover as much ground as they can.

"We're going to go roughly 20 miles a day,” said Leonard.

It's a challenge for two men in their 70s, both cancer survivors. And Leonard has had both knees replaced.

"Even though we have the will, we've got to count on our old wheels," said Leonard.

"We've got the desire to do it and it means a lot to us, so that's the way we'll do it," said Blake.

The walk could take seven months to a year to complete. The men hope all their steps represent a stand they are taking to help veterans.

"All these injured veterans, they deserve a second chance to get their life back in order," said Blake.