If you're baking the shells, I would think that it would be like a sugar cookie...
I assume that you're just leaving them empty til the day you serve, then add your pudding and curd that day, so it should last several days.
Pecan ones should be good too. They're best on the day you make them, but if you keep them a few days, I'd refresh them in the oven for a short time on the day you serve.
But I'm just guessing - it usually disappears on the day I make them smileys/smile.gif