Thank you very much, that was very useful.
You can fine tune how many versions should be kept or for how long. E.g. does not make sense to delete any version before 180 days (for deep glacier) as you pay for its storage anyway.
I wouldn't have thought about it. One thing I'm missing though (or I didn't get right) is being able to specify "exponential" increments (for example 3 monthly and 2 yearly versions). But these syncs are so infrequent that you may as well just use "5 latest versions".
While this isn't an AWS forum, do you remember by any chance if you specified number or versions in noncurrent versioning dialog or left it blank? Not sure if left blank it will keep maximum number of versions possible (100) or none at all.
I'm looking forward to find out how restoring previous versions will work. Thanks a lot for mentioning --s3-version-at (and --s3-version) option. I'm going to sync this bucket again now and test them.
Completed form:
By the way I wouldn't have thought about looking at the option "Permanently delete noncurrent versions of objects" at first, so thanks as well for mentioning that it's possible to specify maximum number of days. Option "Days after objects become noncurrent" didn't sound at first like "after objects becomes noncurrent wait for this amount of days" and more like "make these object noncurrent after this amount of days". But hopefully it will work now (and these new lifecycle charges won't be too taxing).