The only curd that I have kept over several days is passion fruit curd, simply because I made such a large batch while I had the juice on hand. I can’t remember exactly now, but I think I kept it refrigerated for about a week and made several desserts with it. Rose says in the P&PB;that curd can be kept up to three weeks. What I did notice, however, is that it lost its flavor intensity after a few days. It still tasted fine, it just didn’t pack a punch anymore. I would say fresh within a couple of days will have the best flavor, but it should be safe to keep it longer as the eggs are sufficiently cooked.