Not sure what you mean - what happens if you don't rebuild the previews?
I mean, as soon as you make a develop adjustment, 1:1 preview is out of date - that's just how Lightroom works. Is that all that's happening, or something else..
In other words, if you don't make an adjustment (since 1:1 preview built), it should still be fresh - isn't it staying fresh for you?
If not staying fresh when no develop settings changing, then maybe your preview sub-system (data) is wonked - try deleting catalog previews.lrdata folder.
The symptom I'm seeing is this:
I build all 1:1 previews so that I can zoom to 1-1 without waiting for an inordinate amount of time. Fine, now zooming is fast. A day or so later I notice that I have to wait a fairly long time to zoom, while Lightroom says "loading". When I ask to build all 1:1 previews it seems to take a long time again, as if Lightroom has discarded ALL 1:1 previews.
Thanks for your help,
Sent from my iPad
Whether that's normal behavior or not depends on whether any develop adjustments have been made, and you didn't mention anything about that.
Consider re-reading my previous post.
If Lr is behaving abnormally (I *think* I gave enough info for you to ascertain - did I?), try the suggested remedy.
Or, what trshaner said below ;-}
No, in fact I have it set to never discard 1:1 previews. At this time I have plenty of disk storage space and would rather save the time it takes to render the previews "on demand".
Sent from my iPad
I build all 1:1 previews so that I can zoom to 1-1 without waiting for an inordinate amount of time
Where are you zooming in? Library or Develop? Do you understand that those 1:1 previews (stored in Yourcatalog Previews.lrdata) are used only in the Library Loupe view? Previews displayed in Develop are derived from data stored in the CR Cache folder and read into memory and retained there only temporarily - if you zoom into an image in Develop it takes a few seconds to build the display (but not very long because only the on-screen section needs to be built) and if you then go to another image and then back to the first one, it will load almost instantly because the data is still in memory. If, however, you go from image #2 to a third image and then back to #1, it will load more slowly again because the data has been flushed from memory and has to be read from the CR Cache again.
Since I do most of my sorting of heroes and zeroes before importing (in BreezeBrowser Pro), I never do a wholesale creation of 1:1 Library previews. If I ever (rarely) need to zoom in the Library module, LR will create one then.