Why? Humans live about twice as long now as we use to in the middle ages, there is no indication that has effected our perception of time.
I'll have to disagree.
When human life expectencies were under 40 years, there was no concept that child labor could/should be outlawed or at least strictly regulated. Training in the military would have started when a person was about 12 or so. Marriageable age was about the same (actual marriages, not mere betrothals).
Now, most first world nations structure their societies in ways that extends the concept of childhood through the teen years, and some might even argue that it extends into the early twenties- if you're under age 25, you'll definitely have trouble doing things like renting a car (in the US, at least).
On the end of the life scale, we can expect perhaps 20-30 years retirement- unimaginable in the middle ages- and have to plan for that period by saving during our earning years. There are even afflictions that almost exclusively attack the over 50 bunch so they weren't even noticed until life expectancies topped that mark. Now, geriatric care accounts for the biggest single category of medical expenses in first world nations.
Now, expand that concept into a life span of 500 years (dwarves) or 1000 years (elves). A human's drive to earn a PHD by age 30 would seem ridiculous, especially since it comes with the sacrifice of other aspects of growth as a person- perhaps less exercise than is healthy, or being distanced from personal relations. An elf in a world of humans could accumulate the equivalent knowledge in 100 years, all while being fully capable of persuing everything life had to offer because he knows that at the young age of 130, he'd still have hundreds of years to use his knowledge professionally...and would actually be able to personally experience the acceleration of technological improvement.
A dwarf with access to modern banking could concievably amass a fortune belittling Bill Gates' simply by working steadily and saving at a modest rate, and allowing the power of compound interest to work in his favor. An investment at 3% will double in 24 years, so a $5000 savings account becomes $80,000 in 100 years, $1,280,000 in 200 years, and over 20 million in 300 years- that is all without additional deposits. And I can tell you now, I personally know investment bankers who have managed $5000 accounts at 20%+ interest rates for the past 20 years. IOW, who needs to burn yourself out to earn a dollar? Not Gimli!
Consider history. Today, historians and legal theorists try to divine the intent of the drafters of the US Constitution from what they wrote... What if they could actually talk to them about their intent? Or could talk to someone who did? What if that person was you?