I liked to read the game's manual when I was on my way home to finally play the said game.
With the fake excuse of saving nature, manuals were reduced to a mere and pointless health warning. However, there are games that have quite large manuals, which are not filled with game tips, but with another products from the same publisher. Saving nature my butt. Saving money maybe?
So I kind of understand you Plastic, worry not.
Back to +.
It works like this.
You have...let's say 10 free games there right now. When update comes, they swap two-three older ones for two-three new ones. Once you download the game, you can play it for as long as you are subscribed to +. As soon as subscription ends, you can't use any of the + content until you renew your subscription.
No need to worry about space. After you finish the game, or don't want to play it anymore, you can delete it from your HDD. If you'll want to play the game again, let's say a half year from it's download date, when it's no longer in the + free games offer, you can still have it. Once you download something from PSN Store, you can download it again, whenever you want for unlimited number of times. It will be placed in your download history. Still free, no charge. This applies to anything downloaded from PSN Store. Once you download it, it's yours and you can download it again for free anytime for any number of times.
Personally, I don't have + because of free games, but because of it's cloud storage feature. You have a 1 GB space on cloud, where you can back-up and download any of your save files. ANY, even those copy protected, like Dark Souls. Unlike some games, copy protected save files can't be copied to a USB flash drive. So in a case when the file gets corrupted, you're screwed and have to start from scratch. Happnened to me two times in DkS.
PS+ back you up with the storage function. I have it set to automatically turn on my PS3 at 6AM, download any patches, new trailers etc, sync my trophies and upload all my save files. You can choose which games to upload, or not manually, so it won't rewrite you a back up save file.
It has one drawback. Copy protected save files can be downloaded only once per 24 hours and first download is possible 24 hours after upload. Minor issue if you ask me.