I'm born in SF but have been bi-coastal (living in both NY and SF) for 10+years. I built the San Francisco apartment in my childhood home so that I could go back and forth seasonally. My Brooklyn apartment has been a steady continuous work of love. I am ususally in California for the winter and New York for the Spring/Fall. Summer location depends on family and work schedules.
I like to keep both places clean and comfortable & can happily give you any advise on local things to do in either city