Here's my 2 bits: Sometimes people will tell you it's not worth your time to do various things to be thrifty and frugal. However, whether any given activity is worth it is entirely up to the individual.
To me, thriftiness is not just about saving money. It's about making the best use of the resources you have. For me, one of my most precious resources is TIME.
There are some things that money cannot buy, and time is one of them. No matter how much money we save, we struggle to save time. But then, what's more valuable; time or money?
Time is money, or so goes the cliche. There's merit to that well-known phrase and many others. A person can't buy time, another cliche, so why not save it as the greatest resource?
Cooking recipes usually date from the time people did not have to save on energy. Many recipes advise to put eggs, or rice or pasta in the water only once it is boiling to cook them. You can put eggs or rice or pasta or potatoes in the cold water and then start heating it.