General-purpose elastomers are engineered for broad, moderate-duty service — they are not designed for the specific chemical, thermal or decompression stresses that critical applications introduce. The most common failure modes are chemical attack from an incompatible process fluid, excessive temperature outside the compound's rated window, rapid gas decompression blistering the elastomer from trapped absorbed gas, swelling from fluid incompatibility, compression set from prolonged load at temperature, low-temperature hardening losing sealing force in cold service, and simply selecting a material family without matching the specific compound to the full application profile. Each of these is preventable with application-led material selection — sharing the complete fluid, temperature, pressure and movement profile before specifying a compound.