This chart showing the government spending priorities of different age groups is pretty striking:
Three of these trends are intuitive. People over 65 are fans of a government program whose main purpose is giving money to people over 65. And you'd expect a population segment made up overwhelmingly of retirees not to be especially concerned about job creation. You'd also expect people under 35 — who may still be in college, or have student debt, or have kids starting to enter school — to care more about education.
The military spending trend is where this gets really interesting. You can think of reasons for why young people would be less inclined to spend a lot on defense. Older people are likelier to be veterans and to have friends who were veterans, for one. But all of the most plausible theories have nothing to do with life cycles. If knowing or being a veteran helps explain this, then one would expect younger people to put a lower priority on defense spending more or less indefinitely, as the all-volunteer military isn't going anywhere, and if anything should be expected to shrink relative to the population.
There's no obvious reason to think the share of adults under 35 who think military spending should be a major priority will grow over time. And if it doesn't, that implies a pretty significant political shift on that issue.