CA requires 175 days for public schools, so that’s what do (although technically homeschooling is considered private school and this doesn’t apply to them). And yes, I too count field trips, but also other activities that we do that I consider beneficial for their growth as human beings.
Having said that, I don’t pay much attention to it. We just do our thing and I just check off dates on the calendar as we go. When we hit the right number of days I turn it in, but if we want to do more stuff, we do it “off the books”. In other words, we do what we need to do for our own family, and by doing that, we end up with plenty of days for the state too.