The recipe I used to make preserved lemons says they're good for a year in the fridge. I think as long as there's no mold growing on them they're probably fine. There's so much salt and acid I don't think bacterial contamination would be a worry.

I agree--as a traditional preservation method, with very high salt and acidity there is unlikely to be any contamination--the only times I've seen any problems would be near the surface if some of the mixture has separated and gotten moldy--so check for abnormalities on the top.

Thanks! That's kind of what I was thinking. It just seems like there's way too much salt and acid for anything much to grow in there!