Most attics perform best with a combination of air sealing first (closing leaks around penetrations and the attic hatch) and then adding enough insulation to hit an appropriate R-value for your climate zone. Blown-in insulation is common because it covers evenly and tops off older insulation well. The “right” recommendation depends on whether you’re insulating the attic floor (typical) or the roofline (less common), plus ventilation and moisture conditions.
