Some airlines allow you to check-in luggage at airport a day before travel. This far I haven't been using that option because the risk of lost luggage concerns me. Is my concern valid? To be more specific, I'm only interested in big international airports.
Luggage gets lost when:
Checking in early reduces the risk of #1, and has no impact on #2, leaving only case #3 to worry about. Breaking that down in turn, there's basically two ways for bags to get stolen:
So if you're in an airport known for theft and you're checking in something you really shouldn't be checking in, then you might want to check in as late as possible. But if you're sensible and put all your valuables in carry-on luggage like you should, then you have nothing to worry about from these guys, and checking in early will reduce the overall odds of it getting lost.
Here are some issues to consider:
Is the airline liable if they lose your luggage while it's been checked in that far ahead of time? If so, to what degree?
Regardless of liability, it's still inconvenient if your luggage is tampered with/something goes missing - and you have to deal with the inconvenience. With some cultures I could leave my luggage on the curb and be fairly confident that it would not get molested. In other cultures I am concerned whenever someone gets too close to my luggage. Do I trust the people holding onto my luggage overnight?
Are the contents of your luggage just some expendable clothes, or are they more critical than that? What will you do if your luggage goes missing?
Looking at everything, is the risk of checking your luggage in early worth the benefit?
To answer your question directly: In certain cultures I would be comfortable checking my luggage in early, with the understanding that there is a small risk that something weird might happen (which also exists when you check it in normally). In other cultures I am concerned every time I check my bags and only do it because I have to do it. I am less concerned about size of the airport and more concerned about the culture of the people handling my luggage.
Personally, I have never checked my luggage in early. It's usually an hour drive to the international airports I use. I would kill two hours in travel (there and back) just to be able to sleep in an extra hour on the travel day. Plus, I'm working and need the stuff in my bags.