why do i need to redownload files from the cloud almost everytime i want to open a document in numbers and pages?

I can't find a source to back this up, but I think the design of those documents is "cloud storage" only.

Apple promotes the use of iCloud drive by saying you can work across devices with the same document. They only way that is doable is if the latest edits are sent back to the cloud after working with the file, to be viewable in your other device.

If rev. 23 was on an iPad and you wanted to work with it on your Mac... you'd have to fire up the iPad and sync.

hyperbolea wrote:

When i go to open up a document in either Pages, or Numbers, it often is unavailable and i need to redownload it to open the document. What causes this to happen and is there a way to prevent them from disappearing from the tablet?

The master files themselves live in your iCloud storage area and what is kept in your device is a local cache. Every time you go to open one, it will try to check the iCloud copy to update the local cache if necessary (e.g. in case you've edited it in another device since using it on the current device). That check can take a moment if your internet connection is not great.

Are you editing these documents from other devices? With older versions of iOS I sometimes had "collisions" of versions as devices and iCloud were not synchronizing correctly or in a timely manner. Since iOS 9 though it's been pretty smooth - I edit pages and numbers docs on my MacBook Pro, iPad air2, iPad Pro and sometimes even my iPhone. On cellular data, I'll sometimes tap a document and there is a lag to open and I see the green upload/download bar as the doc updates from the cloud version.

If you are not trying to maximize battery life and have an up to date iOS version, try enabling background processing for pages and numbers so they can check for version changes in the background and keep your local cache current.