I never tell her about a purchase because she defaults to an anti-purchase posture. I just let the delivery happen when its too late for her to protest. I have only bought/sold guitars as of the last 2 years so the activity is kind of new for both of us. I keep a semi-constant number of geets such that if I buy one then I will sell another so as not to just accumulate them. She has now found a comfort zone with my hobby, and it certainly helps that I do not buy boats, guns, or golf clubs like many others in our family.