.backup file extension management?

Where exactly are you seeing these ".backup" files? Be very specific.

Try searching your hard drive for ".backup" and see what turns up. I doubt it has anything to do with Pages, but Apple could have changed this since the last version I'm running. but if you only see .backup files for Pages documents, then that would seem to point to a new "feature" of Pages.

Then I think we've solved the mystery behind those files. You can't really control where they go unless you physically move them to another folder, but you can control whether or not they get created.

If you go to the Preferences > General section of Pages, you can deselect the box that says "Back up previous version when saving" and that will stop those files from being created.

I'm guessing here, because I don't run Snow Leopard, even though I just got back from helping someone with their Snow Leopard system (and Pages, coincidentally). I believe this is a new feature for all of the iWork apps (after iWork '09, since I haven't seen it in my versions, though I admit I'm not looking for it. But it's never happened to me, so that's what leads me to this conclusion.

I haven't seen it in any other apps on Snow Leopard yet, but as I said, I'm not looking for it, either.

Well, I was wrong after all! It turns out that the Backup feature is in iWork documents for '08, '09, and '11. It might also be in versions before '08, but I don't have any of those, so I can't say for certain.

You can't set an interval for saving your work (at least not that anyone is aware of yet); Mac OS X does that automatically on it's own schedule. For example, when you're composing a new email message, Mail saves it after about 1 minute as a Draft, and it continues to do this until you send the message, so if your system crashes or the power goes out, that Draft message will still be therre when you restart your Mac. Macs are very reliable, as is Mac OS X, so I think you're worryiing too much about possibly losing data. While it can happen any time, in practice it doesn't happen that often.

Yes, that .backup file is just a copy of the last version you worked on, but that's the point. If you lost the original, you still have the backup. Apple isn't in the business of providing backup solutions for drives; that's for other software developers to do. You don't need to backup every few minutes; once a day is sufficient, unless you're running a business that serves and stores lots of data on servers.

If you want a good backup solution for everything on your system, I'd suggest SuperDuper. It let's you create a bootable backup of your entire system, and keep it updated by backing up only those files that have changed since the last backup. It's very inexpensive,a nd you get a free trial with limitations removed after purchase.

As for Lion, I'd advise against installing it, ever. Many things change in Lion, for the worse. This is just my opinion, but since Tiger, Apple seems to have been focused on adding "features" of dubious nature, and removing things for no good reason.

I haven't yet had the opportunity to work on a Lion system yet, but I'm told by several people in the forums that are ranked at Level 9 and 10 that there is an Autosave feature for most, if not all Apple applications in Lion. I've also read that elsewhere on the web.

But given the problems that Lion introduces with other changes to how everything works (or doesn't work, depending on your opinion of progress), I'd never run it on my system and I wouldn't recommend it to any client, either. iCloud is one of those things that holds no interest for me.

Just my opinion.

Do you mind if I ask you what kind of problems you have found with Lion?

One glaring example: the Save As… function is gone in Apple applications. Instead of that, you have to use Duplicate, which doesn't work the same, because you are duplicating the file, then you have to manually change the name in Finder.

The fact that you have to download Lion to install it and the hours it takes when you don't have the necessary bandwidth are additional problems, along with the fact that the User is required to make a DVD backup of Lion (assuming they have the capability) in case they have a hard disk catastrophe are additional reasons not to ever install Lion.

That's not progress. Whomever greenlighted those things doesn't have a clue as to how Users really work.