Kate deserves our thanks for taking Waimakariri off Clayton Cosgrove, and hopefully her successor can keep it. She also did some very good work in her former portfolios such as industrial relations.
Katrina has been a very hard working local MP in wellington, and had to endure several campaigns against Charles Chauvel, which could get pretty nasty. She's also well respected for her work last term as a select committee chair.
Kate entered Parliament in 2005 and Katrina in 2007. Their decisions to retire show that National is serious about continual renewal, and this is a real contrast to Labour where they have their MPs who entered Parliament in the 1980s still insisting they will never ever retire.
Renewal offers opportunities for National, but also challenges. Obviously both Kate and Katrina and female, and National needs to be pro-active about recruiting and supporting talented women to stand for Parliament. I don't mean there should be quotas or guarantees of selections etc. I mean that National will benefit from having as many great candidate to choose from as possible – but you can't just wait for people to come forward – you need to also go out and find them.
So far six National MPs have said they will retire in 2014 and rumour has it there could be anywhere from another one to six. These are not retirements because they think National will lose (the current public polls have been pretty good for National), but because they are accepting that you come in, make a good contribution, and then give someone else a turn.
A significant factor in whether National gets further terms will be its ability to rejuvenate. It is generally harder to do it in government, than in Opposition. The fact that Labour appears to be doing almost no rejuvenation this election, and National is doing a significant amount, is encouraging.