No one knows better than Maine Sen. Susan Collins how difficult it can be to go more than 18 years without missing a single vote in Washington — except, perhaps, her staff.

When the Republican travels home for the weekend, they're in charge of closely watching airlines to ensure her plane is on time and hasn't been canceled. And during Maine's brutal, snowy winters, that can be a herculean task.

"It probably puts some stress on my staff," Collins said with a laugh.

It appears to have paid off.

Collins on Thursday became just the third U.S. senator to cast 6,000 consecutive votes. It's a feat she believes shows her constituents that she's committed to her job, which she says is particularly important at a time when the public's opinion of government is so low.

"This is the way that I can help assure the people that I'm privileged to represent that I'm doing everything I can to make sure their voices are heard," said Collins.

She reached the milestone on two roll call votes related to the Iran nuclear deal.

Collins' unblemished record track follows a path blazed by her mentor, the late Sen. Margaret Chase Smith, who never missed a roll call until she was sidelined by surgery after 2,941 votes.

"I'm not sure surgery, a tsunami, or the most wicked Maine nor'easter could stop the woman who occupies Margaret Chase Smith's seat today," Majority Leader Mitch McConnell said Thursday on the Senate floor.

While she's the longest sitting senator to never have missed a vote, Republican Chuck Grassley of Iowa has a longer voting streak. He hasn't missed a vote since 1993 and cast his 7,442th consecutive vote in August.

And Collins has quite a bit of work if she wants to knock former Sen. William Proxmire from the No. 1 spot. The Wisconsin Democrat cast 10,252 consecutive votes between 1966 and 1988.

"That's a record," Collins said, "that I think will endure the test of time."

For Collins, keeping her streak alive hasn't always been easy.

She once twisted her ankle while racing into the Senate before managing to vote just as the as the gavel was coming down. Another time, she was already at the airport and had to rush back to the Capitol when a last-minute vote was called.