Repairing and Sewing on Elastic

Dear users, dear authors,
If the elastic on a pair of underwear breaks, you could theoretically sew on a new elastic band. Does anyone still do that these days, or do people usually just throw them away? 

Is it easy to replace the elastic waistband/drawstring casing on a comfortable pair of pants or a skirt?

As long as it hasn’t come off completely, you can repair it. It works pretty well up to about a third of the way, maybe even halfway, but if it’s more than that, it won’t fit as well if sewn by hand.

Drawstrings are easy. Pull out the old elastic, thread the new one back in using a safety pin, sew it together, and you’re done.