I’ve got a Zenbook flip 13 OLED. I don’t worry about any of that suspend/hibernate stuff. It turns off the screen and, I’m pretty sure, the wireless interface when I close the lid. I think this is mostly Ubuntu default behavior, although I did some customization when I first got it.
Sitting idle, I get an estimate of ~12 hours of battery left right now (starting with 80%). This is why I don’t worry about hibernate; idle power consumption is low enough on modern hardware.
When I actually start working, it depends on what I’m doing; actively using wifi seems to bring me down to more like 5 hours remaining. I’m sure I could burn through the battery by cranking up the CPU, but the, it isn’t like Windows will somehow make the CPU consume less power in C0.
When I am travelling, I have limited charging capabilities and want to continue working wherever I left - even if I did not open the laptop for 2 days. That only leaves hibernation. I had a linux laptop that could do that reliable, but for whatever reasons, the newer models of different brands I tried always had hickups and this is unaccaptable for me. I want to work with my laptop, not work on my laptop.
Suspend seemed to work out-of-the-box. I’m not sure how long the battery would last in suspend; the 12 hours estimate was with the screen on and wifi on, just not actively in use.
I just set up hibernate; since I don’t care about hibernate, I didn’t set up my swap partition large enough. Using a swapfile instead is slightly trickier but still pretty trivial. The steps listed here worked fine: https://askubuntu.com/a/1367244
I don't think I had any linux references - the parent to mine had emacs and vim maybe that's what you were thinking of - at any rate being a crappy work computer it of course runs Windows. It's a Lenovo.
On an "old, near unusable machine"? Be happy if Windows doesn't run out of memory when opening the menu. There are Linux distributions that come packed with all the firmware you could want if that's your cup of tea. This is not a Windows vs Linux issue, but even so you can get a stripped down distribution to give old hardware new life.
(also the parent post was edited by now and the linux references I was refering to removed)