This will likely make me unpopular quickly but if you don't see a UL listing I would be looking to replace them. I know lights are expensive and people have great success with China boxes but it only gets worse from here. If you haven't seen the BRS black box episode check it out on the Tube, but in short every single part in there is the absolute cheapest crap they can get to work, pretty much the reason none of the U.S. retailers will stock/sell them. They do have known safety issues, they do not (in most cases) meet the electrical standards and usually fail in scary ways. As an electrician I am biased, house fires are really, really bad and its just not worth the savings in the end. Any light can fail and its almost always scary so try and stack the deck in your favor, like I said the older they get the more likely they will fail, how is the only real question. Sorry I know its not what anyone wants to hear but I did not see it mentioned in the replies. Just my 2 cents, good luck