In my opinion, the ‘social class’ of a person and family, could be ascertained, in how they perceive this phrase.
Growing up in our house, ‘Take care of your pennies~ because your pounds are already blooming spoken for!’ was always quoted. I’m 47 years old, and I actually thought that was the original phrase. It was only very recently, after chatting to a lady from a different part of the country, who’d ‘corrected’ me when I used it, that I realised it wasn’t, and figured that maybe it’s a families financial state that determines how it’s said.
We never had any spare cash when I was younger, so pennies were really important, whenever we did manage to save some, you could guarantee there’d be an unexpected bill/repair, or one of us would be needing new school shoes or having a school trip, something would always pop up that would claim the pennies back.