So, as a person who came to the US in his late 20s in '95 from a country where Halloween was not "celebrated" (of course, now it is has expanded there, too, like in many other countries, fueled by the incentive to sell stuff) I have had an outsider's PoV of the celebrations over the years, here's my chronology in chronological order with my son:
1. Baby Halloween: When you have children this is from birth to approx. 4yrs old, where they don't have much input into costumes so parents can buy the cutest, funniest costume, e.g. a small cow or a bumble bee.
2. Kid Halloween: From about 5 yrs to 11yrs, when kids join you in costume planning and are so infatuated with candy its cure. Some Halloween decorations may still be scary for them :-)
3. Teen Halloween: From about 12yrs old to perhaps 13-14 yrs old. Halloween is a guilty pleasure for these kids, who think they are now too old. You see them still collecting candy but not in costume and using pillowcases for loot
4. Sexy Halloween: Starts around 18 yrs old and covers college years and single adulthood. This is the realm of spooky houses, sexy witches, skimpy costumes
5. Interlude: Early years of marriage, when (4) is fading but you don't have kids yet. You still go out to parties but they are not that wild.
6. Grandkid Halloween: You get to live (1) again but you have much more time!
3.a. 14-17 yrs old. Once you're old enough to work and buy your own candy but still too young to find an unsupervised party, Halloween briefly loses its allure, except maybe as an outlet for a little mischief.