How did you spend your last big birthday?
Some plan it months in advance; for others turning 30, 40 or 50 is a day like any other. In German, there's actually a verb for having a big birthday. "Nullen" literally means "to zero."
While concluding a decade can be a joyous occasion, it can bring mixed emotions the higher the other digits get. However, once you reach 100, it's no longer referred to as "nullen" because then you've got two zeroes instead of one. Now that's something to celebrate!