The answer to this question is entirely up to you. While replacing all your doors with nice, solid core upgrades will certainly add resale value to your home, sometimes finances and living situations prohibit such an undertaking. If a full replacement is off the table, start by tackling the rooms you most want to be fitted with sound control measures. The best soundproof doors are those that provide moments of peace and quiet within your hectic day, so bedrooms, dens, and theater rooms are popular locations. You can add solid or soundproof doors to whichever rooms need them most and add more as life dictates.