Even those in good health should prepare, so far as is reasonable for a trip to hospital.
I recently spent some weeks in hospital and was very glad of preparations made.

In particular having a bag packed that contained useful items.
6 nightshirts
6 pyjama trousers
Other clothing.
A mains/battery radio.
A flashlight and spare batteries.
Several paperback books.
Laptop PC and charger.
Book of sudoku puzzles.
Notebook and pens.

I was particularly glad of the nightwear as use of this enabled me to largely avoid the ridiculous open backed hospital gowns.

The flashlight was useful for reading in bed as one room had no light over the bed, it was a storeroom and not intended for patient care.

Items not packed, and found to be wanted.
A decent wool blanket, hospital blankets are almost useless, too small, too thin, and made of polyester.
A spare laptop PC as the only one with me failed.

For a few little luxuries, I was impressed that both ebay, and a supermarket home delivery service delivered to the bedside.

Good list!

And don't forget to leave your jewelry, watch, and large bill money at home.

No watch or jewellery. I took some cash with me but spent very little.
Supermarket home delivery very useful. Hospital food just about acceptable in one hospital, but much better at the other one.

Free internet and phone calls.

I gave permission for students and trainees to prod and poke me and to practice on me.

It's also smart to pack a 'support bag' for anyone that will be assisting you providing support or visiting.

Wife got suddenly sick and it turned into a long term slog. After a time I developed a daily bag for myself
iPad
e-reader
life savers & hard candy, cough drops
power pack / cords
always charged cell phone
the "usual" EDC
bottle of soda and/or water

I could grab snacks at vending and/or the 'gift shop' and the cafeteria had very good food and a LOT of choices. I am sure it would be situational for anyone but if you have to go spend a bunch of time at hospital, rehab, nursing home etc. the above can help.

I've also got a substantial binder with files, folders and documents for supporting the ongoing situation that is 'grab and go' too.

I would add some cheap earplugs and one of those masks to block the light if you're trying to sleep with the lights on.

And my apologies to the roommate I had years ago, for the evening that I was drunk on morphine and talking up a storm.

When my friend’s dad was in the hospital, I brought a Sudoku puzzle book. I wish I had brought more. You had the foresight to get more than I did.

A neighbours kid was recently admitted to hospital, and her parents packed a bag similar to mine.

Pajama trousers, long nightshirts.
Bathrobe.
laptop PC.
personal music player.
Cell phone.
Assorted puzzle books.

The child reported that they were well cared for, and the food was good.

Items not packed and later wanted. Bath towels because hospital one are "horrid", a wool blanket from home because "uncle Adam says hospital one are no good" and more books.

Cell phone cord and charger

Interesting subject as I'll be going in for a procedure in about a month with a 10-21 day stay. Here's my list:

Blanket
Tush Cush Cushion

Laptop Computer
Extension Cord
Extended Screen
USB Power Cube/Cord
Bluetooth Trackball

Reading Glasses
Kindle

Cell Phone Charger
Flashlight
Earplugs

Toiletries Kit
Toothpaste
Toothbrush Electric
Toothbrush Manual
Tongue Cleaner
GUM Tooth Picks

Electric Shaver
Electric Mini-Shaver
Deodorant
Shampoo
Shower Head, Wrenches and Teflon Tape

Hand Sanitizer w/ Aloe
Good T.P.
Good Kleenex
Dude Wipes

Relief Band, batteries and conductivity gel (https://reliefband.com/)

Underpants
Nylon Swim Shorts
Lightweight Loose Pants
Button Down Short Sleeve Shirts
Non-Slip Socks
Short Socks
Athletic Shoes

As well, we will have a refer in the room and access to a Microwave so Sue will be bringing snacks and such and since the food sucks, most of my meals will be brought in by Sue. Fun and games...

Checkbook.

What is a "check?"

You're fortunate to be going in at a time of your choosing! I hope it goes well.

It's this thing you write on and then they take money from you.

Good luck with your procedure. 10 - 21 days is a long haul.

So, Mr. Ritter - how's the recuperation going?

Been home for a few weeks; https://kniferights.org/legislative-update/dont-get-dead-1/

Still pretty weak, but getting better. Occasional issues which doc just says, yep, that happen.s Numbers are still looking good. Will start on maintenance chemo and such later this month. Still stuck at home for the most part. Have to wear an N95 mask if I go out. Nasty stuff in AZ dust they don't want me dealing with for a while. Still rebuilding my immune system. Hair is gone, still don't recognize myself in the mirror. Who is that guy staring back at me? 46 years with a beard. They estimate 3 months give or take until hair will grow back and might be any color, from snow white to original black. My appetite is good and on a high protean diet. Hanging in there. Thanks for asking.

I'm glad to hear you're on the mend, Doug!

"Occasional issues which doc just says, yep, that happens."

"Ah . . . yeah, thanks Doc."

I hope nothing else "happens." Hang in there.