"Ignoring very basic maintenance like clearing debris causing water to pool on roofs. And ignoring caulking around windows.
My Aunt and Uncle had a beautiful Spanish mission-style house from the 1920s. And it was in really good condition when they bought it.
Roughly 20-25 years later, the only thing in halfway decent condition were the wood floors. Roof was shot and actively leaking in multiple rooms. Causing plaster ceilings to just fall.
Exterior walls were destroyed. Framing was completely destroyed, and again plaster just falling off he walls.
The house stood in great condition for over 70 years. And through minor neglect, fell apart in the last 20."