Why collectors watch them
Modular buildings are display-friendly, recognisable, and often collected as a street. Once older releases become difficult to find in strong condition, collectors may pay a premium for clean examples.
Sealed condition matters
Large boxes show shelf wear easily. Seals, corners, surface dents, sun fading, and moisture damage should all be photographed and disclosed.
Used sets need careful checking
Used modular buildings can contain thousands of pieces. Check minifigures, rare elements, manuals, and colour consistency before assuming a set is complete.