What I ACTUALLY do all day is to work in a handful of different roles: family member, community member (especially volunteering), athlete, investments manager, project manager, gardener, builder. Before I retired, I worked very difficult hours and traveled. And my areas of focus now almost entirely align with what I missed most when I was so oriented towards that work life. I still find it magical to spend time in the garden right after dawn where my biggest worry is forgetting where I set down my coffee mug and having my dog dig a hole near the asparagus.
When I hear that question, I try to understand where it is coming from. Is the question really about what ACTIVITIES fill my day? Then I answer in a literal way based on what I did yesterday or last week. Other times, I understand the question to be about my IDENTITY; since I'm not job-centered, how do I define myself? In those cases, I answer in terms of identity. I had difficult and high flying job that fed my competitive nature. Over time, I found myself less ambitious and needing more grounding and balance. I'm very grateful for time now available for my family and to volunteer helping kids learn to read, etc. When I retired, I had a huge backlog of projects around the house that I'm still working through.
If I have the sense that the question comes from financial nosiness, I often respond by saying that I really like having an open schedule to do anything that I want. That such freedom was what motivated me to plan well and work very hard in a difficult field and save 1/2 of my and partner's income.
I haven't sensed an underlying question of: "what do you contribute to society now?" If I did get that question directly or indirectly, I think my answer would be something like this. When I was focused on my career, I did virtually nothing for my community other than pay taxes and vote. In fact, it felt like a selfish mode focused on advancement. Now that I'm retired, I put much more time and energy into my community.