I’m 40. I like 18yo’s. I think they make nice eye candy. I could even have sex with one legally. But The act of actually doing such a thing just seems gross to me.
So this leaves me wondering: When I’m 60, will I think the same thing about 30-somethings?
I think you’re on to something when you implied that, for many people, it’s not so much that the age range you are attracted to changes much, but rather that your definition of “attraction” changes. When you’re 18, 18-year-olds are “attractive as eye candy + potential mate”; by the time you’re 35, they’re just “eye candy”; and when you reach 50, they’re reduced further*, to “mildly pleasurable, fleeting distraction in your day’s events”, at most.
(*“Reduced”, sexually speaking. The positive side of this is that said reduction opens the door to seeing them as more complete human beings than just as sexual attractions.)
ETA: To answer the OP: I guess this means that, when you’re 50, 30-year-olds could be seen as, and appreciated pleasurably as, “potential mates (or friends with benefits)” – plus some degree of sexual attraction, but not as strong as what had once been felt for 18 year olds.
Mmm… I’m 40, and the idea of having sex with an 18 year old is gross, because they’re kids. (Someone will be along any moment to say they’re adults as though I’m unclear on the concept of the legal age of majority. I’m not, it’s just not relevant to whether I want to have sex with them. I don’t. I consider them children.)
Now, 25 - 30 year olds, I won’t consider them as life partners, but I’ll sure as hell have sex with them. I suspect I’ll feel the same way when I’m 60. I also suspect they won’t be quite as much of an option. 
It obviously doesn’t work this way for everyone since you see rich old men marrying women younger than their kids, but I think that having kids accelerates the process too. I’m in my mid 40’s and my kids are 21 and 22 - the idea of being involved with anyone their age or even closer to their age than mine is just too odd for comfort. Despite the attraction of a hard bodied young pool boy to pander to my every whim I would have to say that the age range in which I would consider a replacement mate (not that I need or want one) would definitely be over 30. Heck even the 30 yr olds I work with seem impossibly young some days.
This seems to be a very reasonable outlook for people who have kids (or nieces or nephews) or know kids that would be around that age.
Anecdotally, when my mom was 38 she remarried a 25 year old guy. And I was 15. It felt pretty creepy at the time, because I was closer to his age than she was.
I’m 35 and just can’t see being interested in a guy under about 25 as anything other than eye candy; there’s too much of a life-experience gap there. However, there is some damn fine under-25 eye candy out there.
I’m 71 and I view 18 year old girls as children; sexual attraction just isn’t there. In my case, the lack of sexual interest is pretty much independent of age. YMMV.
I’m 41. I used to use a formula to determine the minimum age woman that I’d have sex with: 1/2 my age plus 7.
But then I met the perfect 23-year old and that formula went out the window. Now I let the government set my limit for me.
This. There can certainly be sexual attraction. But I can’t imagine we’d have anything to talk about. I am 36, btw.
When I was 41 I dated a 25-year-old. The attraction was definitely very strong, she was a clever girl, and we got on really well, but her lack of emotional maturity drove me half insane to the point where I had to get her out of my life.
Now I’m 43. I realised I was “thinking older” earlier this year when I stood next to two extremely shapely 19-year-olds in a bar and though I appreciated their form, facially they seemed like children to me, and their conversation was stunningly vacuous. No real attraction. (Though I guess if I encountered them naked in my bed I may have changed my mind.)
The girls / women I find attractive have always been pretty much my own age. I’m 60, but first noticed this when I was in my thirties. Ten years younger to five years older seems to be my viewing window.
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I’m 37, and love spring days when the hot college/high school chicks jog along my commute route. But I couldn’t have a conversation with most of them, which is important for anything other than eye candy.
Joe
As a differing opinion, there are some of us younger folks who are primarily attracted to middle-aged-plus people. The generation gap only tends to be a problem when I get above a 20-year or so age difference.
–chaoticbear, 24-year-old dirty old man
The problem, I think, is that the women likely to be attracted back and follow through on it are uh, cougars. And probably not looking for anything more than a fling.
I’m not saying it’s impossible to establish a good relationship with someone significantly older. It is possible. But lots of people looking to bridge that gap have unsavory motivations. (30 year old guy and 18 year old girl? Oozes skeezy!)
I mean look back at yourself 5 years ago, and imagine how your 5-year-ago self would have looked on yourself 5 years before that. Don’t you always think you were a complete dunce 5 years ago in terms of life experience, at least? In 5 years you’ll be saying the same thing about your “now” self. Once you get up to a 20 year age difference… well, that is a whole lot of life yet unlived for one half of the relationship.
I had a sexual relationship with a nice 18 year old (male) when I was in my 30s. Y’all are right, there really isn’t too much to talk about, but he sure was pretty. If I weren’t monogamously attached now I’d still fish in that pond, but I wouldn’t keep them, only catch and release.
Thankfully my taste in potential partners matured with me. I believe the MILF and cougar memes are to blame, but I’m frequently flirted with by 18-30 year olds. Unless I’m blatantly propositioned they have no signature on my radar. Those who come on strong seem to be conflating me with the moaning, surgically enhanced and heavily made-up MILF’s of porn fantasy. That offends me in ways I can’t justify.
Also…pretty young boys seem somehow effeminent to me, but I can’t justify that, either.
Give me smile lines, freckles, and life experience over youthful folly any day. So… no more than 10 years younger than me need apply.
Sigh…smile lines 
New wife is 13 years younger than me. When we first hooked up we were both very frank about our doubts about anything permanent–this was just friends with benefits. We were married 5 months later and are quite happy. But I gotta be honest, what age-related aggravations there are, are with me feeling old because I remember lots of stuff from before she was born. Sure, she has an Atari, but I had an Atari. In some ways I feel like a well-loved dinosaur: If I talk Atari with folks my age it’s reminscing, but with her it’s research.
But she wasn’t 18 when we got together–those are kids.
I can’t see myself dating an 18 year old. They look nice in Playboy, but I couldn’t seriously date anyone that immature.
30 is the age I find most interesting. Doesn’t matter if I’m 45, 55, 65 or 75. A thirty year old has life experiences. They’ve been in serious relationships. I can’t imagine not being attracted to someone in their thirties.
I’m 62 and I not only think 18-year-olds are great eye candy, but I’d happily date one under the right circumstances. I’ve never been one to think that younger girls should be off limits to older guys (or younger men for older women). In my parents’ generation, women frequently got married at 17 or 18 years of age, and by the time she was 21 my mother had three kids. So I didn’t grow up in the era of thinking of 18-year-olds as children. As long as everyone’s legal I don’t see what difference the age of the people involved should make. There are benefits and drawbacks to both parties when there’s a significant age difference, but on balance I think the benefits outweigh the drawbacks by quite a bit. Associating with younger people generally helps keep your thinking and your attitudes younger and your life more lively, and older people generally treat their younger paramours well - less jealousy, more stability, more philosophical and forgiving, more appreciative, etc. - and often can provide entree into worlds and a way of life that a younger person isn’t likely to experience otherwise. Both parties need to be aware though that they aren’t likely to mesh mentally and that the relationship isn’t likely to last.
I dated a few teen-to-early twenties girls when I was in my late forties and early fifties and I always enjoyed the wistful, envious glances I got from the men when we were out…and the glares I got from the women.