From a security standpoint, what are the differences that must be addressed between data with a day-long confidentiality timeliness and data with timeliness of a year or more?
As a practical matter, in 2015, there is no difference provided we are talking about encryption using computing systems.
When data were encrypted by hand, or with relatively slow machines, it made a difference. "We attack at dawn" could be encrypted with a much faster but weaker algorithm than "Swiss bank account: 123456." Claude Shannon made note of this during World War II when he said that the amount of secrecy needed determines the amount of work that’s appropriate.
Today, you'd use strong encryption for both because the time saving from using a weaker algorithm over, say, AES, is insignificant.
Furthermore, a weak-but-fast algorithm will fall very quickly today because the adversary will surely be using computers even if you are not. The weak-but-fast algorithm is no longer useful.