One of the answers to this question is generating some discussion about the cost and lifetime of a satellite. The question is, will a satellite become cheaper when you can design it for a shorter lifetime?
At the moment, commercial geostationary satellites are designed for an on-orbit lifetime of 15 years, limited by propellant supply. Satellite operators would like to increase that by using more efficient engines.
If you were to build a satellite for half that lifetime, would it get much cheaper?
My guess: it wouldn't get much cheaper; the only savings you have is in fuel (and hence, size of the fuel tank and launch mass). Electronics still have to be rated for space, halving the projected lifetime isn't going to change the fundamentals of producing and qualifying the parts.