There are two issues here Leonie. The age one is that once you are over 30, every year you go without PHI means an extra surcharge that you will have to pay on your premiums if you ever do take out PHI. This is to reduce the number of people who don't take out PHI until they are older and ill. For the system to work they rely on young, healthy people to have PHI to subside the others.

There is also the tax surcharge, which is once you earn a certain amount, you pay a medicare surcharge if you don't have PHI.