It's true that many pieces have a similar look about them, but the trained eye looks beyond that in judging the worth of a piece - Chinese antique furniture should be judged by the workmanship involved in its origin creation, and its design.
Carpenters were constrained by the rules and convention dictated in the "lu ban jin" (the classic manual for carpentry, as well as architecture). Their challenge was to create a piece using the manual, but yet distinguishable by his own personal trademarks using styles of the times.
The original construction of pieces did not include nails or pins - carpenters used different forms of tongues, groves, or mortise and tenon constructions - complete restoration is possible without causing any damage to the wood.
Most of the furniture we find has been in use for well over one hundred years without any regular maintenance or restoration. If a piece is restored without using the proper tools and techniques, the patina (the natural texture and graininess of wood that evolves naturally through years of use) of the wood can be destroyed.