I bought my first games when I joined, and I can still download them. There isn't a limit to download your games, but you may want to keep a local backup since it's usually quicker than downloading the game from scratch.

Unless something goes horribly wrong with the licensing or GOG goes down you'll be able to download them from your shelf.

Don't worry, you can download your games whenever you want. Even if a game gets removed from sale, it will still stay in your library.

I would still suggest to keep back-ups on a HDD though. You never know what will happen in the future.

As other users have said, you can download games even if they get removed from the store (i still have space rangers 2 in my shelf even though it was removed for instance). But it's always safe to download them on a HDD, just in case.

You need to download your GOG games before the Sun expands outward far enough that it starts to destroy all life on Earth. GOG.com can't guarantee availability of the games once Solar apocalypse begins however they'll probably do their best anyway. I wouldn't doubt if they launch a satellite containing a server with all of the games into a lisajous orbit at a Lagrange point out around Jupiter just to be on the safe side. But even then, we can't guarantee that we'll have a craft big enough to escape the dying planet on our way out into the Cosmos to look for a new home and still have time for everyone to download from the satellite as we pass by due to bandwidth and time constraints, so it's always a good idea to keep a local backup copy on hard disk to bring with you if you're one of the lucky ones to be selected for the final cosmic voyage.

Update: Yes, that is likely to be some 500 million years from now, but advancements in science and medical technology in the last decade have been quite revolutionary and within our lifetimes it is possible that we may develop the biotechnology to extend life essentially forever. Well, until the Sun does it's thing anyway. I'm just saying.

*paid

Everyone on Alderaan thought they were under no time constraints to download their games; look what happened to them.

Everyone tried downloading them at the same time through the Death Star, and the resulting beam of data proved too much for the poor planet?

Good point. It's not like the Empire built that thing just so those idiotic peons could use it as a comm satellite. Serves em right!

Thanks everybody. Glad to hear about that. I better start downloading. And making backups.