Would they? I don't find myself thinking "I have only at most 80 more years to live, so I'll jaywalk here, risk be damned". Do people really do those kind of mental calculations? It might be me still being relatively young, but having 60-80 years in front of me feels more like +∞, and I have to keep constantly reminding myself that my time is limited.
I'd wager that the only relevant scale for people to think is weeks/month; there wouldn't be much difference felt between 60 years, 600 years and +∞.
People don't _think_ about it, but a sense of our time limit is part of our 'human condition'. e.g the phrase 'you only live once'. 'You only live once, but for 700 years' has quite a different feel to it.
I'd wager that the only relevant scale for people to think is weeks/month; there wouldn't be much difference felt between 60 years, 600 years and +∞.