Prepositions – ‘I Left Them (at) Home’

They both sound natural, but I'd say there's a subtle difference... Maybe other native speakers could weigh in to make sure this difference isn't a regional thing.

To me, the phrase "to your left" means "about ninety degrees to the left of where you're facing," and the phrase "on your left" means more generally "to the left of where you're facing."

In your example, if we were walking down the street, I'd probably know exactly which building you were talking about if you said "the building to your left," but I might ask, "Which one?" if you said "the building on your left." (You might be referring to a couple different buildings.)

I'd also say there are subtle differences when you further modify "on/to your left." For example, it sounds much better to me to say, "the next few buildings on your left" than "the next few buildings to your left."

Similarly, if you said "all the buildings to your left," I'd interpret that to mean the buildings that I would see if I turned ninety degrees to my left, possibly including buildings behind me. If you said "all the buildings on your left", I'd interpret that to mean the buildings in front of me on the left hand side of the street.

You've probably read or heard expressions like "I'm at John's house right now" or "Everyone is at my house today."

However, even though it may seem logical, you can't say brought X at home. The preposition at doesn't work with bring in the sense of identifying a destination location.

It sounds like you are trying to say where the event or action of bringing occurred, as opposed to the destination place of the bringing. And that may only somewhat work in some limited circumstances where context fills in the to or for part of bring, but not very well:

Sally needs to bring candy for everyone this time. I brought two candy bars at the game last time, so why do I have to do it again? (I brought two candy bars for everyone at the game last time).

So, before home you want to use to or in.