What Is Insurance?
Insurance is a policy designed to make sure that you are back to your original position (in most cases) after an accident or disaster, such as a flood or burglary, than you were beforehand. It is obvious that mainly cash compensation is awarded rather the original content itself.
There are dozens of different types of insurance, from insurance that you have to take out by law (such as car insurance), to policies that it's a good idea to have (such as contents insurance) to those that are 'nice to have' rather than necessities.
Insurance can provide compensation only for the actual value of property. It cannot cover the loss of sentimental value, for example.
There must be a large number of similar risks so that the likelihood of a claim can be spread among other policyholders. It must be possible for insurers to calculate the chance of loss so that a premium can be set which matches the risk.
Losses must not be deliberate and not inevitable. Clearly, you could not buy fire insurance for a house which was already burning nor life insurance for someone on his or her deathbed.
Lastly, there are some risks which have financial implications so vast that they can be dealt with only by the state. These risks (mainly those arising from war or the major escape of nuclear or radioactive material) are normally not insurable.