I have been making occasion cards since I was a child as they were always class art projects -- something to do for our parents -- by teachers who were not artists and had to come up with something to keep kids occupied! I continue the practice, however, enjoying hoarding bits of interesting paper, and then as an occasion comes up seeing how I can vary the annual theme. Since I have recently photographed all the cards from my Mum's archive, that she has kept over the years, I can easily compare them. Here is a sample of Valentine's Day cards I made for my Mum, starting with this one from 2002, using bits of wrapping paper and coloured construction paper as a base.
This one is from 2008, the base card being white corrugated cardboard and the hearts and other elements are made of a spongey material with an adhesive backing.
This card from 2010 uses white card stock as a base, some wrapping paper scraps, and various coloured paper scraps. I also made use of a silver pen!
I used some heavy green card stock for the base of this 2013 card, The white paper with white and gold bits threaded through it is specialised wrapping paper. The red heart is a bit of an envelope I think, and the red background is simple coloured photocopy stock.
The card for 2016 made use of red card stock as a base, and several bits of coloured paper scraps to make the hearts. Goes to show how one symbol, a heart, can be used repeatedly to create a different card. There were many more variations in the archive, but I thought these provided a good example.