This is one of those things where everyone who has an opinion about it is so opinionated that I invariably switch off and miss the crux of the debate.

But basically, your lower puncta are where 80% of the drainage occurs (remember that gravity effect?) leaving only 20% for your upper puncta. (Incidentally, anybody who is plugged refers to them as "lowers" and "uppers" — whether they’re referring to the plugs or the puncta, who knows or cares?) Anyway, the most common approach seems to be to plug only the lower ducts and, in certain cases, depending on how the eyes react to having lowers, subsequently plug the uppers. Some people say this is all wrong, you should first plug the uppers where less drainage takes place, and plug the lowers afterwards. We really couldn’t care less, but we feel obliged to mention it in case your eye doctor has strong proclivities one way or another.

If you plug both the lowers and the uppers, you are, you guessed it, quadraplugged! Strangely enough we don’t know very many people who found quadraplugging beneficial. Most people we know that tried it eventually had the uppers removed. — But not all, and you never know what might help you, so if your doctor wants you to, you might as well try it because you can probably get them taken back out. (Though, come to think of it, that’s something you should talk to him about before you have them put in.)