I am in full agreement with IAmSinistar. Just want to add that external HDs are your friend.

You'd think that, but I've had it happen more than once and I still forget to keep completely thorough backups.

I have really important things backed up, but I guess I get lazy with games because I've been able to come to GOG and fetch them whenever I want. It's good to be reminded that it might not always be the case.

I confess towards that tendency at times as well. I try to always have multiple backups of the things that I could never retrieve (my photos, writing, artworks, correspondences, etc). But I can be more lax about things like GOG games when I know I can get them again. I think you are doing fine if you are ensuring your irreplaceable stuff is backed up somewhere, and then attending to the rest when practical.

Another thing that can be useful, assuming one is quite invested in one's data, is getting either a fire safe or a bank safe deposit box. Not only are these great for your personal papers, but they might a nice container for a hard drive of critical data. The fire safe perhaps a little less so, since fire can still technically scramble a hard drive below the paper ignition point.

Sometimes I still want to cry when I think of all the Amiga work of mine I lost. Game designs, artwork, programs, custom fonts. About all that remains are some BASIC progs I wrote. :(

I only dl them if they are small enough.
Now i have 77 games on GOG with over 1GB size that i wait to dl till i have a better con.....except Sacrifice that game is just evil incarnate :p

I learned the hard way about a year ago, now I've almost become paranoid when it comes to backing up programs. I'll probably pick up another drive at some point just to have a back up of my back up, updating it periodically and keep it at a separate location... I guess pretty much what you are suggesting. One crash was enough for me.

Yes, I have two main external drives, and I try to cycle between them so that they don't become a single point of failure either. Now that I have a fire safe I'll probably keep the most current one in there as well, if there's room with all the papers.

One other solution, at least for the smaller and more important files, is to use an online drive as another form of backup. DropBox and its ilk can be a good way to keep crucial files apart from your own hardware. But generally those aren't big enough, or bandwidth-y enough, to back up terabytes to. At least not for the average individual consumer.

You can all be proud, you've gotten me to back up almost 8 shelves of my GOG library onto an external hard drive. I've been taking the opportunity to look through all the wallpapers, and added a few I like to my desktop rotation. There are some really neat concept artworks too, especially in the RPGs.

I'd never really paid that much attention to the size of game files before, as long as there was enough room on my computer, but it's amazing how much difference there is between a 486 MB Fallout and a 1.5 GB Fallout Tactics. Now I've just reached The Witcher, so, er... that'll be going for a while. Guess I'll go find something else to work on.

Oh thank you for that program, I'll surely try it.
Did you manage to obtain the single updated ISOs or just files \ other "pieces"?

Yeah, let's hope that GOG will understand that having to redownload full games after each new OS version is not optimal..