How Long Should My Life Policy Last
Mortgage Cover - this should be at least for the term of the mortgage. If you take a level policy (also see above) there will be greater potential future flexibility (and potential future cost savings) if you take a policy for longer than the term actually required for your current mortgage - e.g. to retirement age.
Family Protection - if you have dependents, you should consider taking the cover till at least their 21st birthday. Taking the cover up to your retirement age also carries huge potential benefits.