Half and Half is a mixture of equal parts whole milk and light cream. It is commonly available in the U.S. as a stepping stone to heavy cream. In England, Half and Half is called Half Cream. Because light cream is not widely available where I live I specify Half and Half as the ingredient to use in cream-based drink recipes.
Light cream has more butterfat so using it will result in a richer drink, but I find Half and Half to be rich enough for my tastes (in most cases). Where it is not I will specify a heavier form of cream. You also benefit from the fact that the calories are not going to dent your waist line as quickly as cream will.
Normal Half and Half will keep until the date printed on the package which is usually about a week or so from date of purchase. For a little more money you can ultra-pasteurized Half and Half which will last several weeks or sometimes a month.
Why yes, there are several ways to make Half and Half if you don't have any in your fridge:
Do you have another substitute for Half and Half? I'm all ears if you do.