Limit of Photos

It will depend on your patience, how long you are prepared to wait for a library repair or the background processes to finish.

When I ask the attendants at the Apple Store, they will usually say "Not larger than 25000 photos". As Yer_Man said, there is no published limit for the maximum size of a Photos library. We only know, that Photos has been able to migrate Arpeture Libraries and iPhoto Libraries to Photos, which requires to be able to hold at least one million items. But it would be unrealistic, to expect Photos to work well with such a large library.

My largest library has currently 57000 photos and videos. Photos is working well and is quite responsive, when browsing the library. but some tasks are very, very slow. It takes more than a month to get all photos and videos scanned. It took more than two weeks for the duplicates album to appear. Repairing the library takes several hours. And using more than a-hundred smart albums is making Photos nearly unresponsive. The first upload into iCloud took nearly two weeks. Working with photos is possible even for a very large library, but the regular maintainance, necessary after system updates, will be very slow, if the library is getting too large.

The People album cannot be structured with with folders, so t is hard to browse, if you have many entries in the People album, the list of keywords also has no structure. It helps to keep the libraries small and focussed on specific topics and people, to keep the lists short, to avoid scrolling.

And if you are planning to use iCloud Photos and sync the photos to your mobile devices, consider the available storage on your mobile devices. They will probably be the bottleneck.

There is no posted limit, and certainly there are mentions of Libraries in excess of 100k on here. So, the obvious limit will be disk space. However, also bear in mind that Photos is a processor intensive app at times, and more powerful machines with more RAW will manage large libraries better.

I think you're being somewhat unrealistic here. This is a give-away app aimed at folks taking snaps with their devices and wanting to share them across these devices easily. Just because it will do more doesn't mean it's optimised for that. You can write a doctoral thesis with TextEdit, but you'll have a much better experience using an app like Scrivener, Word or Mellel.

I just wish Apple would be upfront and clear about their products' limitations.

They are. But the information you want is dependent not only on hardware, which can vary wildly, but also the user's perception of what is acceptable - as Léonie's post demonstrates. So, as I said, the limit of size is dependent on disk space. What you regard as acceptable is something that Apple cannot know. So, how slow is too slow for you but not for Léonie, or vice versa, and how are Apple to know this?

Simply springing changes on us, e.g., from iPhotos to Photos, from iTunes to Music, should be illegal.

Apart from things like media coverage, which was extensive on both of these changes, the Apple website for the relevant versions of the OS and the applications also covered these changes comprehensively. So, nothing was 'sprung' on anybody. And to characterise product evolution and development as 'megalomaniacal' is beyond absurd. None of these changes were forced on you. You didn't have to upgrade, you could simply have stayed as you were. Both sets of changes offered a simple progression to migrate to the newer app. If you installed these upgrades without the most basic checks in advance to understand what was being installed, and was then surprised, that's down to you.

You're absolutely right about the countless hours we have to spend managing their products' shortcomings...

And this is consumer choice. If you find the application doesn't meet your needs then by all means use a different one for the job. There are alternatives, and they are all more powerful than Photos, as you would expect when they are not give-away apps.