The only constant, we're told, is change itself. So, there is nothing new under the sun. And we can think of some obvious things - The sun rises and sets. That's a constant. Tides rise and fall.
Seasons come and go.
Then there are the constants in the midst of apparent change. We may have changed over the centuries from cooking over a fire to cooking in a microwave, but there's still the daily routine of getting hungry, finding and preparing food to quell the hunger. We used to sleep in caves, then wood shacks, and now huge, centrally heated homes. But we still run the cycle of working, getting tired, sleeping, and working again. We have moved from carving symbols in clay tablets to whipping packets of information across the internet and around the world.