If your Tulips last only a couple of days they must be pretty old when you get them. I suspect that they have spend a lot of time in storage(refrigerated).Shall we say that if you get some freshly cut tulips they could last the best part of a fortnight depending on their weight(there are Tulips and then there are Tulips!!) because commercial growers treat them with silver nitrate which prolongs active life.Tulips from the garden do not have this treatment so will have a natural cycle which isn't as long.. However the question is whether the flower's cycle is played out on display at your place or in someone's fridge.