For reasons ranging from political ambition to frustration with “crazy bills,’’ many of the state’s elder statesmen are leaving the Capitol.

More than a lifetime’s worth of experience will walk away from the Legislature at the end of the year. Fifteen lawmakers have reached their term limits, announced their retirement from politics or decided to run for other public offices. They will take with them a collective 130 years of legislative experience.

Three other seasoned lawmakers are destined to lose an election this year as they go head-to-head with their fellow lawmakers in the 2016 election.

All told, the Legislature is certain to lose between 148 and 150 years of cumulative lawmaking experience at the end of 2016, depending on the outcome of one of the lawmaker-on-lawmaker races.

And that doesn’t include any surprise upsets of incumbents on Election Night.

Capitol observers, especially the old-timers, often lament that the Legislature as a body lacks institutional knowledge.

Stan Barnes, who served as a legislator for six years starting in 1989, and has worked as a lobbyist for more than 20 years, said the shakeup coming in 2017 is unprecedented.

“The deck of cards that is the 90 lawmakers is about to shuffle in a way I haven’t seen in 28 sessions,” he said.

The shakeup is due to a “confluence of events that’s kind of rare,” Barnes said. And the re-shuffling at the Capitol will leave the House and Senate with new leaders and mostly new leadership teams, both on the Republican and Democratic sides.

So many lawmakers leaving the chambers at once strips the Capitol of some of its most valuable players and damages the institution, he said.

“It’s bad for the Senate, it’s bad for the House, it’s bad for the entire institution… It’s like a strange storm is sweeping away a lot of the institutional knowledge,” Barnes said.

Barry Aarons, who has been lobbying at the Capitol for more than four decades, said history often repeats itself.

But the cast of characters at the Capitol changes even more quickly. And by the time history makes a loop, most of the elected officials don’t even remember what had happened the first time.

Instead, it falls to legislative staff and lobbyists like Barnes and Aarons to remember the issues the Legislature has tackled in past decades, and the solutions that have or haven’t worked.

“The good news is lobbyists become the ones who have the most institutional memory. And the bad news is lobbyists become the ones who have the most institutional memory,” Aarons joked.

Senate President Andy Biggs, who is running for Congress this year after 14 years at the Capitol, blamed the lack of institutional knowledge on term limits, which restrict lawmakers to four consecutive two-year terms in either chamber.

Biggs repeated the often-heard refrain that term limits empower lobbyists and staff over lawmakers, and strip the Legislature of its history-keepers.

“You see things that old-timers would say, ‘We never would have done it that way.’ Some of that’s good, some of that’s not so good, but you do lose a lot of institutional knowledge,” he said.

But ambition is the prime culprit robbing the Capitol of experienced lawmakers. Nine legislators, including Biggs, are leaving this year because they chose to run for another office (or are facing a challenge from a fellow lawmaker attempting to move from the House to the Senate.)

Five lawmakers have hit their limit of four consecutive terms in one chamber of the Legislature, forcing them to retire from politics or seek a different elective office.

Another six lawmakers are simply walking away, opting instead to return to their private lives and other jobs.

Walking away

Democratic Rep. Debbie McCune Davis recently announced that she will not seek re-election in 2016, ending her 30-year career as a lawmaker and giving up her title as the longest-serving legislator currently in either chamber.

McCune Davis was first elected to the House in 1979 and she stayed for 16 years. In 1992, voters enacted term limits. Although that wouldn’t have forced McCune Davis out of the Legislature until 2000, she decided to impose them on herself and not seek re-election in 1994.

Almost a decade later, she came back. She returned to the House in 2003, then jumped over to the Senate in 2007. In 2011, she moved back to the House.

But after 30 years of walking the halls of the Capitol, McCune Davis decided to call it quits at the end of this year.

The rise of “dark money” in elections is the prime reason she has decided not to run again. She just didn’t want to go through another election.

“I think as a candidate, you put your name on the line,” McCune Davis said. “And you want to feel like you can offer a message to the voters. And I don’t think that’s the case anymore. With dark money and independent expenditure committees, I think you don’t have much control of the message anymore.”

For example, mailers were prepared promoting her with a message she didn’t like.

“And remember that those folks do it with a sense of expectation, that you somehow owe them something. And I’m uncomfortable with that,” she said.

McCune Davis is nostalgic for the days of friendlier relations between lawmakers in opposing parties. Now, she said, politics is more contentious and lawmakers are all in a hurry to change aspects of government they haven’t taken the time to understand.

“I’ve seen changes in the behavior patterns as well. People are in a hurry to make a name for themselves, and the process of learning the process has gone by the wayside,” she said.

Instead, she’s going back to private life and her job as the executive director of her public health nonprofit, Arizona Partnership for Immunization.

But McCune Davis is still hesitant to leave the Capitol because when long-time lawmakers like herself and others check out, the Legislature loses “people who ask relevant questions.”

“There’s just something about having been down here and knowing what’s been tried before that worked or didn’t work,” she said.

Tired of “crazy bills’’

Democratic Rep. Bruce Wheeler is also leaving the Capitol of his own accord, and not seeking another elected office. He first served in the Legislature in 1975 for two years, before returning in 2011. But Wheeler said the last years have been frustrating and he simply can’t bring himself to run for the House again as a member of the minority party.

“I’m tired of the arrogance of power, and I’m tired of voting no on these bat-(expletive) crazy bills,” he said.

Other offices

Many other lawmakers are leaving for the chance to roam in greener pastures. Few aspiring politicians can resist the opportunity to seek a higher office, and this year two congressional districts are wide open for the taking.

Those districts have drawn four lawmakers so far, including the speaker of the House and Senate president.

Biggs, the Senate president, recently jumped into the race to replace U.S. Rep. Matt Salmon, who announced his retirement earlier this month. House Appropriations Committee Chairman Justin Olson is also leaving the Capitol for a chance at Salmon’s seat in Arizona’s 5th Congressional District.

House Speaker David Gowan is running for Arizona’s 1st Congressional District, which U.S. Rep. Ann Kirkpatrick is vacating. Gowan, however, doesn’t have much of a choice. He has hit his term limits in the House, and his Senate seatmate isn’t going anywhere. Gowan will be joined in the CD1 race by another lawmaker – Republican Sen. Carlyle Begay.

But it’s not just congressional races that are drawing talent away from the Capitol.

Republican Rep. Rick Gray is departing for a chance at statewide office. He is seeking a seat on the Arizona Corporation Commission.

And Republican Rep. Doug Coleman is giving up life at the Capitol for a chance at an elected job closer to his constituents. He’s is seeking a seat on the Pinal County Board of Supervisors.

Democratic Sen. Lynn Pancrazi is also seeking a job closer to home. She’s leaving to run for the Yuma County Board of Supervisors.

Term limits

For all the fury directed by old-timers at term limits, few lawmakers even reach their term limit. Only five lawmakers this year are being forced out due to term limits.

Republican Rep. David Stevens is one of them.

And like many lawmakers, he’s not a fan of term limits. Stevens said he understands the intent behind the policy, but thinks term limits have had the unintended consequence of kicking out some of the best lawmakers – himself included.

“(Term limits are) too long for a bad legislator, and too short for a good one,” he quipped.

He doesn’t want to leave and he said he plans to return after spending two or four years away. In the meantime, he’s running for Cochise County recorder. But his true love, he said, is the Legislature.

Stevens said it can take years to become an effective lawmaker, or to even learn how to make a proper motion on the floor. And he feels he’s just hitting his stride.

“My first four years was learning the job. In the last three and a half I’ve been doing my job,” he said. “It’s almost like K-12. From kindergarten to third grade, you’re learning to read. From third grade on, you’re reading to learn.”

Stevens recalled being a freshman lawmaker dealing with a complex water issue. His seatmate, who had served in the Legislature in the 1990s, remembered tackling that same issue, and steered him in the right direction. Without that help from someone with institutional knowledge, he would have repeated the same mistakes lawmakers made a decade before, and never learned from history.

“That knowledge is invaluable. And when we walk out of here, we take that knowledge with us,” he said.