Recently I have noticed a couple of threads that make reference to why things were done a certain way, that may not be appropriate now for various reasons. One example was letting things cool on the counter before chilling them in the "ice box". When you were trying to keep the ice from melting an the other items from getting too warm that made sense. Other topics involve the use of various ingredients.
I am in my early 50s and even in that time I have seen much change, the demise of the milkman for one, no grocery delivery for another. The vast majority of us don't need to use up stale bread, milk that is on the edge, or an overabundance of eggs from happy chickens. Yet many recipes and cooking techniques are based on the premise of having those things around as a matter of course. I am a single guy... I don't drink milk often, and it is rare for me to just happen to have it in the house. On the other hand I have an abundance (or at least an opportunity for an abundance) of canned and frozen meats, vegetables, fruits, etc. I have a plethora of electrical appliances that make short work out of chopping, mixing, blending, and cooking.
I still remember my grandmother making milkshakes for 6 grandsons with a hand cranked mixer in a big mixing bowl. They were cool and delicious, but not very thick. Another aunt had a very prolific lemon tree. But for lemonade all the lemons were juiced using a hand held wooden reamer. Friends of mine who grew up in Hawaii have memories of husking and opening coconuts, shredding the meat and squeezing out the milk (not the water in the center) to make various dishes for family parties - a lot of work. My grandmother's copy of the Joy of Cooking has information on how to rend lard and prepare wild game that I don't think I noticed in the most recent edition. Most of the supermarkets near me don't even sell lard (or buttermilk for that matter).
What adaptations have other chowhounders made to their techniques and family recipes that reflect the changing times?