How long will duck confit last?

Duck confit was designed as a way to preserve the meat through the lean winter months. Properly stowed, it can probably last a year or two.

It's impossible to say how long your confit will last based on your vague description, although you could freeze the legs for future consumption.

My own personal guidelines for freezer food is to consume within three months, mostly from an inventory/space control perspective. While I am sure the high fat content in duck confit legs would favor prolonged storage, I am not one to try to figure out what the outer limits of storage will be before I see freezer-based quality deterioration.

In any case, good luck.