So I'm a first-time Mac owner (but have owned iOS devices for years). My family has a large photo library, around 400 GB of photos and videos. We've had iCloud Photo Library (IPL) activated on our iPhones for several years and have a good amount of media there already (around 100 GB each for my wife and I). Now that we have a Mac, I want to go all-in on Apple's photo ecosystem by importing our older photos & videos (at least the best ones out of that additional 400 GB of media) into our iCloud accounts to make the available on all our devices. My questions: With the latest update to Sierra, how reliable is IPL for large libraries now? I will need to turn "Optimize Storage" on in Sierra (I have a 2016 rMB with a 512 GB drive). How will Time Machine handle photo backups? I don't like the idea of only relying on Apple to do my backups (what if my account gets wiped for some reason). I would like a local backup of everything, including my recent iPhone media that is only in iCloud right now. Is Time Machine smart about this, or do I have to go through a manual "download all" procedure? When I import our older media into iCloud, I will use my account, but then want to use iCloud Photo Sharing to allow my wife to see them. I've found in the past that I can't reliably share too many photos this way at once - I have to break them up into chunks of 50 or so, or else my phone's photo app hangs. Haven't tried after the recent OS updates. Do others have this same experience? Any suggestions on this workflow?