I think some of that came from poor families. People only had one set of "sunday clothes" ... or only one nice outfit, so it needed special care

if you messed it up, you might not have anything nice to wear for a year or so - not out of punishment, but out of thats all that could be afforded.

Today its so different. Most people can afford more than one nice outfit of clothing.

That was always my understanding of sunday clothes .. it was all you could afford.