Easy mode is for someone rushing for unlock scenes or unlock a full skill NG+ mode.
If you play in hard mode, you will need that full skill character.
In hard mode with a full skill character, if you sleep 6 hour per day, that will give you 10 energy, and the rest 18 hour will drain you 13.5 energy, so you need a moka($100) and a coffee in kitchen to full fill your need. and you also need to eat 4 times per day to keep you from hunger.
I suppose, assuming you don't do activities with increased resource/h reqs. Not to mention how a lot of most important activity reqs are much higher than their actual consumption, so you will definitely need to top off suboptimally which changes the calculation. And need a lot of ng+ money for those daily mokas since work will be getting a quarter income for 4x resource costs.
In any case, it seems kinda weird to me to balance the third difficulty around making even ng++ micromanagement excruciating when there's such a colossal gap between scene viewer mode and the abnormally hard "normal" mode. It seemed like
either doubling energy costs
or halving income/stats/energy gains would have been the obvious way to do normal instead of
both.
Edit: For fun I toggled hard to check how much you get from working. With several promotions, I'm making $34 for -3 energy, -4.8 food, -2.4 clean, -1.8 fun, -4h. Forget daily $100 mokas, that means I barely even cover the cheap pub hamburger that will recover just some of the food (+3.5). I'm starting to wonder if this difficulty is even possible without save scumming on a first playthrough.