The answer is probably “yes” if you:
Have an older home and haven’t added insulation: in a recent survey, only 20% of homes built before 1980 were well insulated;
Are uncomfortably cold in the winter or hot in the summer — adding insulation creates a more uniform temperature and increases comfort;
Build a new house or addition, or install new siding or roofing;
Pay excessive energy bills;
Are concerned about the effect of energy use on the environment.