Generally your asset value is at risk i.e. the assets you have worked hard all your life to build when one of 3 events happen in your life.
If you become sick or injured and cannot work or require money for expensive medical bills you will not be able to fund your lifestyle. Your assets will possibly be diminished or go entirely. Appropriate levels of Insurance are essential if the worst was to happen.
If you die without a properly drafted will, your estate may be affected. Your estate may not go to the right people at the right time and could be at risk from relationship or financial misadventure.
Perhaps the most important but less discussed issue is what would happen to your assets should you be sued and a judgement be taken out against you.