I had cancer eight years ago. While I'd already taken a few year-long breaks before that, cancer reinforced the idea. While I'm not particularly worried about it coming back, I'm certainly not going to bank on living until 90. I also don't have kids right now, but haven't entirely ruled it out. And even if nothing kills me off early and I don't have kids, it's still a lot easier to travel while younger. I've avoided traveling in Europe because that'll be easier when I'm old and arthritic. I don't expect to be backpacking around Africa or motorcycling through South America or sailing around the South Pacific when I'm 80, but I could do a nice railway tour of Western Europe or a cruise around the Mediterranean at any age.