@jclarke It’s simple.
Assign a value to your time. And see whatever action you are about to take are they really saving you money or costing you .
Example: I will use very basic and simple calculation to help with the point.
assuming you earned Rs 1,00,00,000 which means you earned roughly are 27,000 per day or say again roughly Rs 1000 / hour. I am using roundish numbers to keep matters simple .
So value of your time is Rs 1000 / hour.
Now judge how much activities cost you, in your airport example , say cab costs Rs 1000 per trip and you spend 1 hour travelling but bus costs Rs 500 but you need to travel 2 hours, which includes going to bus stop and waiting .
In this example you saved Rs 500 but you spent 1 hour extra which is worth Rs 1000. You are at a net loss of Rs 500.
Now similarly , if you cook your own food, and say you have optimized the whole process and spemt 2 hour prepping cooking and cleaning . So it may cost Rs 2000 in terms of time but say ordering food would have cost you Rs 1000.
So you got to judge the value of your activities and time.
Hope this helps.