I often do intense or random shit for no reason because I dread last times.
Think of these retirees that need home assistance. One day they went out for groceries. At the time they didn't know it but it was the last time they ever would.
One day you will wake up and you won't know it at that moment but it will be the last time you slept in that bed.
Then you will make a coffee for the last time. Then you will feel a pain in your chest and phone 911 as you collapse.
The medics will take you to the ambulance. This will be the last time you ever were in your home. Maybe you'll be thinking "hopefully I'll be home tonight to finish my crosswords". But your crosswords will stay unfinished, next to a cup of cold coffee.
So I climb and vault over stuff when hiking like a Call of Duty bunnyhopper, because one day I'll wonder when was the last time I did.
And I suddenly sprint for no reason because one day these retirees ran as fast as their legs could carry them, just for the hell of it, like all kids do. And they never did again. And one day they ran fast, out of necessity this time, and they never did again. And one day they did a weak jog, maybe to catch a bus or something, and they never did again.
When I'm old and broken, which isn't infinitely far in the future, I want my last times not to be too far in the past. Imagine being lazy in your green years, and as dusk approaches you wish you were able to exert yourself... except you didn't when you still had the strength to do so.
Don't wait for an excuse or a need to do a physical feat you haven't done in years. One day you will sit down and never get up again.