You can get a new set of robes by searching the cupboard again for the torn robes and then remaking them with needle and thread. You cannot get another set of torn robes if you already have a set of torn robes or robe of Elidnis in your possession (including in the bank). However, you can use the Drop trick to get extra sets by dropping your robes before searching the cupboard. This gets you a new set of torn robes, which you can mend when you wish. Unlike Desert clothing, the Robes of Elidinis do not provide any protection from Desert heat.