If the kit is currently in production, I open it right away just in case I need to request a replacement part from the manufacturer. Using the instructions, I thoroughly inventory and examine every part. I make sure the body isn't warped and the clear parts are not cracked or scratched. I also bag up the tires, clear parts and decals if they are not already bagged from the manufacturer, especially the tires. Tires seem to ruin clears parts and decals. Last November I bought Revell's 1962 Impala SS and was shocked to find the body had a crushed roof. I usually request replacement parts from Revell but in this case I just exchanged the kit for another one from the store. It paid to open the kit right away.