Two products in particular, Universal Life and Whole Life, are designed to meet long-term needs by taking advantage of allowances by the government for cash accumulation on a tax-exempt basis. Basically, you pay more than the actual cost for the coverage, and the excess money is invested within the structure of the plan. What's more, that money is not taxed annually as it grows.
The design and function of the two products is quite different - they appeal to individuals with different risk profiles, personalities, and investment styles - but their purpose is the same: to maximize the value of your estate. Not only can tax-exempt life insurance cover your estate needs, it can be a significant asset within your overall portfolio.