If you fly multiple hops, there is no way to guarantee this, service quality varies wildly ie across Europe.
Some airports are known to be 'black holes' for luggage, from dealings with Swissport who handles lost&found everywhere, they mentioned that Fiumicino airport near Rome didn't have stellar reputation to say politely, and Barcelona wasn't that great neither. Had luggage lost on both in rather annoying way - both of them didn't have a clue where it was for more than a week, started saying goodbye to all rather costly equipment like paraglider set in it.
But I've seen stuff get lost in places like Vienna multiple times, so one can't draw any simple conclusions. I see it as a massive room for improvement and automation via 'AI', but that should have been done a decade ago, ie automated barcode scanning isn't novel tech.
It does seem to have improved in general. (From a small sample size as I don't check luggage unless I have to.) United's baggage tracking in their app seems pretty reliable and I toss in an AirTag as a backup which also works well.
Some airports are known to be 'black holes' for luggage, from dealings with Swissport who handles lost&found everywhere, they mentioned that Fiumicino airport near Rome didn't have stellar reputation to say politely, and Barcelona wasn't that great neither. Had luggage lost on both in rather annoying way - both of them didn't have a clue where it was for more than a week, started saying goodbye to all rather costly equipment like paraglider set in it.
But I've seen stuff get lost in places like Vienna multiple times, so one can't draw any simple conclusions. I see it as a massive room for improvement and automation via 'AI', but that should have been done a decade ago, ie automated barcode scanning isn't novel tech.