Our house was built in 1955 and has little wall insulation. Added another R25 in the attic last year and sealed the attic penetrations so now it's time to take care of the walls. Right now they have 2" of rock wool batt. Would dense packed celulose blown in or the slow expanding foam be a better option. The house is paid for and we're not moving untill they wheel us out to the nursing home,hopefully another 35-40 years.