I have a meagre income and I am all but fully retired. I still give 10% maaser to charitable causes both here and abroad. My question is can I use part of my maaser money (a) to buy sefrei kodesh, (b) to travel to my father’s place of burial (say once in 4 years) costing around $400, or to the Ohel of a great sage, (c) to pay for a gift for a Bride & Groom(whether the parents are seemingly well off or not)? Many thanks.
If until now you have directed all the maaser to charity only, you should perform a "hatarat nedarim" (like you do before Rosh HaShana) and explain that you are sorry you did not specify that the money could be used for any purpose of mitzva (Shu"t Y'Chavve Daat III 76). If you have always used your maaser for general mitzva purposes no hatarat nedarim is necessary. A gift for a well-to-do married couple (it is the couple and not the parents whose financial state is important) is not a mitzva.