Even in a downturn however severe, it's easy to forget that there is a constant stream of income flowing into the Kiwisaver providers, which has to go into their investment portfolios, including stocks. So when one stops exposure to stocks in whatever parts of their portfolio, to avoid the paper losses, they also forego the fact that the Kiwisaver provider continues investing in lower priced shares during a downturn.

Personally I used to think Kiwisaver was something I should actively manage, by changing portfolio spreads, but I've come around to thinking it's better to just choose the portfolio spread/balance that suits me overall and forget about it, and let time do it's magic thing.