http://www.shutteractuations.com/
Maximum Shutter Actuations Life Prediction:
Nikon D4:
Kevlar / carbon fibre composite shutter with
400,000 exposure durability
Nikon D3, D3x, D3s:
Kevlar / carbon fibre composite shutter with
300,000 exposure durability
Nikon D800/D800E:
Kevlar / carbon fibre composite shutter with
200,000 exposure durability
Nikon D700:
Kevlar / carbon fibre composite shutter with
150,000 exposure durability *
Nikon D7000, D300s, D300:
Factory tested Shutter life
150,000 actuations
Nikon D5100, D5000, D3100, D3000, D90:
Factory tested Shutter life
100,000 actuations
Nikon Older Models:
Don’t have enough Information, Like D80 is to be said up to 50000 actuations. But Most newest model min have 100k actuations tested on the factory.
If your camera shutter has worn out, you can repair it at your camera service center, it will cost you 100 – 250 $. They will disassemble your camera and replace the shutter with the new one, and reset the shutter count to zero again, and start counting. In other word shutter count is representation of your camera shutter life expectations, not your camera life. After you change your camera shutter you can shoot normal again. Just like your car tire has worn out and you can change a new tire and your car start working again.
I prefer Nikon, I have 2 Nikon D200's, purchased the D300, then sold it to a friend to buy a D700, and just picked up the D800 last week, which I ordered in Feb.
A shutter should almost last you a lifetime, unless your shooting sports.