Yep, my mom makes alot of stuff at home because she doesn't like store bought items.. like garam masala powder and any type of masala for that matter such as bhuna hua zeera, dhania, etc.. she stores them in containers and they last VERY long. also chaat masala, ginger/garlic paste, tomato puree, yogurt all at home.
my mom does that too. She makes her own Garam Masala, Chaat Masala (much better than the ready made ones) her own Nihari and Haleem masala too. What she does with the Onions is she uses the food processor and makes bags of chopped onions when she needs then u can easily just throw them in the salan. They last a long time. She also does the garlic and ginger paste and leaves on in the freezer to freeze and the other in the refrigerator to use whenever she needs it.