Health Insurance
Health insurance is not necessary per se, but it is a very valuable commodity depending on your stage in life. Basically, it will help protect you in the event that you get hurt or fall ill. And you never know when either may happen, so it's nice to know you have something to fall back on.
Many young people feel that they don't need health insurance because of their youth and overall health. Nevertheless, many young people engage in high risk activities such as skiing or mountain climbing. So depending on your lifestyle, you may want to consider getting health insurance even if you are perfectly healthy.
However, as we grow older and start to build families, health insurance becomes increasingly important. Not only to protect your own health but also to cushion your dependants if you were to fall ill or get injured. Also, as we age we are more prone to illness and injury and we may even need to take daily medicines which can be very expensive. For all these reasons, health insurance exists.