The people who say they need 3 cups of black coffee to start their day are just addicts with a high tolerance that experience mild withdrawal symptoms each morning.
If you feel like that, it’s your body crying for you to take a break.
If you like an occasional cup of coffee or energy drink to get through something, then that’s fine. But if you ever feel like one isn’t working like it used to, you should take a break from caffeine to reset your tolerance, not up the dosage like an addict.
Espresso has less caffeine than large mug of drip coffee especially of morning light or medium roasts. And many coffee makers just make twice more water in double shot, not twice more coffee.