Q I have heard that once activated on a Mac, there is no going back from iCloud. Is that correct?

A There is an element of truth, but that is not fully correct. The regular pre-Yosemite iCloud service allows you to store documents and data, accessible from multiple Macs and other systems able to connect to it.

Yosemite and iOS 8 offer iCloud Drive with enhanced features, but once you have converted to that version, there is no option to revert to the older iCloud: it is a one-way trip. In both versions you can always save items stored in iCloud back to local disks, ensuring that you can discontinue Apple’s service or switch to another cloud provider.

Updated from the original, which was submitted for publication in MacUser volume 31 issue 3, 2015, but never appeared.