Cracked, shifted, or broken sidewalk sections can create drainage and trip-hazard problems around a home. Repair or replacement should restore both the surface and the way people move through the property.
A good room addition should solve a space problem without feeling tacked onto the house. Layout, roofline, access, utilities, and interior transitions all play a part.
A room addition works best when it solves a specific problem with the existing house. Start with how the new space should function, then plan size, access, structure, utilities, and finishes around that goal.