(21) She is not afraid of snow for her household,
for all her household are clothed in scarlet.
(22) She makes bed coverings for herself;
her clothing is fine linen and purple.
For this part, let me start with what it meant back then:
Back when this was written, they didn't have a "mall", where they could go and buy a Tshirt, or pick up a new pair of jeans. They did have a market place, where they could buy food and imports, but they didn't really buy too much in the way of clothing. It just wasn't practical. Instead, the women would make it themselves. If the wife/older daughter(s) didn't make clothing for the winter, they would freeze.
But what does the color matter? Why specify the color scarlet? I think it has to do with Solomon making his point clear. While scarlet itself doesn't add warmth, it implies that she took more consideration to what her household wore than letting them walk around in drab, gray colors. Dying clothing took a lot of work.Which means that she cared a lot about her household, enough to spend weeks to dye the clothes she had made for them.
Then next part, "her clothing is fine linen and purple" says that she not only cared about what her household wore, but what she wore, too. She spent time considering her wardrobe, and made sure she didn't end up walking around in a colorless potato sack. She chose her clothing with care and modesty.
Ok, so how does this all apply to us, who just need to go to the mall for the clothes that women would have to make themselves?
Well, when we get married and start a family of our own, this verse calls us to make sure that our children (and husband) have clothes to keep them warm/cool. That they aren't wearing tattered jeans, or shirts that they grew out of years ago. And it doesn't hurt knowing how to sew buttons back on, either. ;)
Also, it calls us now to care about what we wear. Not to just randomly stick our hand in our closet and wear whatever we happen to grab. Not to walk around every single day wearing shabby sweats and guys' T-shirts. To dress with modesty, wearing clothing that compliments your feminine figure, but doesn't cause guys to feel awkward around you.