What is the lifespan of siliconee? Will it crack? Do I need to worry about dry rot or anything like that?

Silicone rubber does not dry rot like latex rubber. Silicone rubber has the longest lifespan of any of the RTV (Room Temperature Vulcanized) rubbers or elastomers. Five year shelf tests show less than 10% loss in properties. With proper care and maintenance, your RealDoll should last many years. There are still first generation RealDolls in existence which are being used and loved after 11 years of service. Your RealDoll will last as long as it is properly maintained.