As well as those who find themselves departing involuntarily courtesy of the electorate, there are a record 33 MSPs – more than a quarter of the current parliament – choosing to stand down, including half of the 26 MSPs who were in the first parliament in 1999.
Some who have decided to call it a day have not been there nearly as long but nevertheless made their mark – like Ruth Davidson, elected an MSP in 2011 and Tory leader just a few months later, before overtaking Labour as the main opposition party at the 2016 Holyrood elections.
Labour’s Neil Findlay, also elected in 2011, has been a strong voice on the left of the party, was a key link with Jeremy Corbyn as UK leader, and campaigned effectively on a series of important causes.
And Jeane Freeman, once political adviser to Labour First Minister Jack McConnell but elected as an SNP MSP in 2016, has been the Health Secretary coping with the Covid pandemic.
But among those saying their fond farewells are many who were there at the start and played their part in the unfolding history of devolution.
Iain Gray was a junior minister in the first Labour-Lib Dem coalition government, later promoted to Cabinet in the “minister for everything” post in charge of enterprise, transport and life-long learning, and served as Labour leader for three years in opposition. Johann Lamont, another former Labour leader, is also going.
Michael Russell was a prominent member of the SNP’s first contingent at Holyrood and once in government served in a succession of top roles.
Always forceful and outspoken, he will be a big loss, as will Alex Neil, another original member. Mr Neil did not always see eye to eye with the leadership and stood against John Swinney to succeed Alex Salmond in 2000, but later served in the Cabinets of both Mr Salmond and Nicola Sturgeon and also proved extremely effective quizzing witnesses at committees.
Other 1999-ers leaving the stage include Roseanna Cunningham, deputy leader when John Swinney was in charge, a leadership contender when he quit and later in the Cabinet; and Linda Fabiani, currently in the limelight as convener of the Salmond committee, but who also had a key role in the parliament’s first big controversy, the Holyrood building project, chairing the group charged with bringing it under control.
Two decades on, it's easy to take the Scottish Parliament for granted and forget that before it was created, Scotland was governed by a handful of ministers appointed by a Westminster government, often of a party opposite to the one most Scots voted for, and answerable to a parliament which never had the time or inclination to deal with Scottish matters properly.
Whatever people might think of the performance of the current Scottish government or its predecessors, devolution represented a major democratic achievement.
And although some of the high hopes of those early days have been disappointed, the shrinking number of the Class of '99 is a loosening of the link with the pioneering spirit and sense of potential which that first parliament embodied.