Ditto! I feel like that's the cool thing about GOG and like I don't fully own the games unless I download and secure them right away... otherwise it's kinda like Steam without needing a launcher

Depending on your collection it can be very easy to backup a couple of thousand games onto a 4-8TB drive. For every large 70GB Cyberpunk game there may be 10-100x more older / Indie titles that are 100-1,000x smaller (eg, VVVVVV = 66MB, Banished = 122MB, Ben There Dan That = 22MB, Beneath A Steel Sky = 87MB, Limbo = 181MB, To The Moon = 101MB, etc). If you own a lot of those, then the size of a whole collection (measured as average per game) will be significantly lower than the average size of last year's 10-most bloated out 50-250GB AAA titles. Maybe even measured in MB / game instead of GB.

True
my ~100 games takes 435 GB and I only dl windows and english versions + goodies.
Cyberpukk takes 100 from it :O

I have 309 (no count 14 demos), back up the half of them and sized about 250 GB. I want to buy a 2 Tb external disk to continue the back up.

I'd like to get a new hard drive and backup my collection, I had to use all my spece for personal photos and videos. I trust that GOG is now going to stut off without a word of head-up. I would make a double copy on 2 drives when it's official that GOG is closing. Until then I'd be cool with just one (but I'd rather like to make a double copy of personal stuff)

I checked it's 340 GB. With even very few mods for some games and the previous i mentioned. Still not all games backed up.
And some goodies not every goodie..

I have a similar amount of games, about 340 on GOG. They’re a mix of old and new games. The offline installers of the 30 largest games take up about 322 GB. The few mods etc. that I saved alongside the offline installers are included. They don’t make up a large portion of the occupied space.

The largest games are

76 GB: Kingdom Come Deliverance
74 GB: XCOM 2 + War of the Chosen
63 GB: Dying Light: The Following
58 GB: The Witcher 2
54 GB: The Witcher 3: Wild Hunt GOTY
48 GB: Deus Ex Mankind Divided
45 GB: Wolfenstein: The New Order
43 GB: Prey
43 GB: Dragon’s Dogma Dark Arisen
40 GB: Darksiders Warmastered Edition
37 GB: Wolfenstein: The Old Blood
31 GB: Elex
30 GB: Phoenix Point Year One Edition
29 GB: Dragon Age Origins
26 GB: Divinity 2 Developer’s Cut
24 GB: Soma
22 GB: Pyre

The smallest games are:

24.6 MB: Bio Menace
25.3 MB: Jill of teh Jungle Trilogy
42.6 MB: Doomdark’s Revenge
50.4 MB: Eye of the Beholder
53.2 MB: Eye of the Beholder 3: Assault on Myth Drannor
61.4 MB: The Lords of Midnight
71.5 MB: Delores - A Thimbleweed Park Miniadventure
73.6 MB: Downwell
93.4 MB: Magic Carpet
101 MB: Star Wars X-Wing (1993)
112 MB: Star Wars Tie Fighter (1994)
122 MB: The Elder Scrolls Arena
129 MB: D.R.O.D. 1: King Dugan’s Dungeon
131 MB: Eye of the Beholder 2: The Legend of Darkmoon
143 MB: Lure of the Temptress
146 MB: The Even More Incredible Machine
150 MB: D.R.O.D. 2: Journey to Rooted Hold
151 MB: Tyrian 2000

All games together take up about 2.3 TB. I regularly update my offline library using gogrepoc.

Why is your Dying Light so large? The installer is around 25.7 GB and the Hellraid DLC is 860 MB. Even installed, if you remove the non-English languages (around 8.5 GB), it will be somewhere under 30 GB.

All of the DRM-FREE titles I own plus the freeware games that I play in total take up 63.2 GB in total. I have 517.8 GB of mods, models and maps for Doom (1993) and UT99.

I back up my games every Friday, if there are changes or updates.

Largest game: Indivisible - 6.4 GB
Smallest game: PicoQuest: Darkness Rising - 685 KB

It was a mistake on my part. I use gogrepoc to automatically download all updates and I forgot to delete the previous version after I downloaded the last update.

NVM I already posted here.

That is what i am doing currently.

I think that's a wise thing to do, since newer version can bring bugs of their own or remove certain features.
This method certainly takes more time and space, but it is worth it.
Out of curiosity, how do you back up your games? External HDDs? If so, on how many and at what capacity?

I use external 4 terabyte drives, 256 or 512 gig SDXC cards, and 100 gig M-discs. The more important things go on SDXCs and M-discs.