A friend of mine once told me that one of her daughters was able to organize family photos by approximate date by looking at what she and her sisters were wearing.

I know what she was talking about. I could do the same just by looking at the sweaters in our own photographs.

While there are always classics, the trendier sweater styles change so quickly. A few years ago in fifth grade, our daughter wore cropped sweaters and cardigans. She layered them over longer tanks and jeans, and that was pretty much the uniform of the day.

Right around the same time, first lady Michelle Obama gave a boost to cardigans, and not just plain ones. Beaded, sequined and even patterned cardigans – from animal prints to splashy florals – showed up everywhere, and everyone seemed to fall in love with three-quarter-length sleeves. As a longtime cardigan fan, I even wrote a column about how I think I loved cardigans before the first lady did.

Soon, ruffles started cascading down sweater fronts, and barely-there open-weave sweaters caught on during the warmer months.

In the meantime, the cropped sweater stage ended for our daughter just as she was outgrowing them, and her new cardigans were longer.

These days I see many pull-over sweaters on teen girls again. Fine gauge ones that tuck neatly into belted jeans. Longer ones – sometimes cable-knit – worn untucked over leggings or skinny jeans. This, of course, was a look I wore – was it two decades ago?

Styles also changed for men. We occasionally catch an episode of the old “Cosby Show,” and laugh at the outrageous sweaters worn by Bill Cosby's Cliff Huxtable character. They look so wrong now.

But many guys wore sweaters like that back in the 1980s. I even bought them for my father. Some men still have them in their closets – a good thing in case an invitation comes up to attend an Ugly Sweater party.

All this sweater talk reminds me of a time when the guys in my extended family were in high school or college and, at Christmastime, all received gifts of the same crew-neck sweater, in different colors. The gift boxes were identical. The wrapping paper was identical. The sweaters were identical. Only the colors were different.

The gift-giving aunt, mother or grandmother probably bought them from Lands' End or L.L. Bean. Or maybe the sweaters all had alligators on them. Anyway, if the guys had worn them at the same time, people would have expected them to start snapping their fingers and burst into song.

So, yes, sweater styles seem to change swiftly. It appears that cropped sweaters are out of the picture at our house, and longer styles are in again. Sometimes, it's hard to keep up.

One thing that never changes, no matter the style. They all need to “lay flat to dry.”