I don't think there were price decreases of the hourly prices for EC2 instances - previous decreases were for traffic, or introducing reserved instances where y

I don't think there were price decreases of the hourly prices for EC2 instances - previous decreases were for traffic, or introducing reserved instances where you get lower price in exchange for commitment. I think trying to factor in future price decreases in an ec2 cost model doesn't make sense - it is too little and unpredictable to worry about. Don't forget that if you reserve an instance for 3 years and Amazon drops prices, you'd get only partial savings on the hourly fraction of the cost. Even as I use Amazon for hosting (instances running full time) I stay away from the 3 yrs reserved instances because I want to be able to reevaluate my options more frequently.