Here are some items for me:
(1) I learned that cats like playing with cat toys. I used to feel that this was teasing the cat, but somebody on an atheist forum told me it is important. It took a while for my cat to understand the concept, but now he enjoys playing and this keeps him from being as bored and depressed.
(2) I learned about ctrl-A and ctrl-C for copying on computers. I use this a lot every day.
(3) I learned about cat water fountains. My cat used to drink unsanitary water from my dirty bathtub and kitchen sink even though I changed his water dish every day. I bought my cat a water fountain, and he never touches the sink anymore. This is important, because cats kidneys often fail when they get older. I think this probably will add some lifespan to my cat
(4) I learned the importance of wet food for my cat. Often cats don't drink enough water, and giving them wet food helps keep them hydrated. Even cheap wet food is good. I use grain-free, but that probably isn't necessary. His breakfast is wet food and the rest of the day he snacks on dry food. The dry food helps keep their teeth clean.
(5) I learned about Go Cat brand cat toys. I have a very realistic mouse wand toy and their famous bird toy. There may be better toys, but these are the best so far.