Since term insurance is temporary, it offers you several different options of how ling you may be insured.
Many life insurance carriers offer term life for a period of 10 up to 30 years.
The most common "terms" available for term policies are 10, 15, 20 and 30 years.
You'll want to consider how long you need coverage - what is the longest period you need protection to accomplish your life insurance goals?
For example, if you want to have life insurance to pay off your mortgage in case you die, you'll want coverage that matches the duration of your mortgage loan which may be 15, 20 or 30 years.
If you want life insurance to pay for your child's college education should you die, you'll want to choose a term that will last until your child reaches age 22 or so, which may mean taking out term insurance for 10, 15 or 20 years depending on the age of you child.
There may be term policies available for 25 years of protection.
Here's how to learn more about term life coverage and how it works.