I don't anymore, but a while back I did. She is a lifer (though she was paroled a few years back). She had been in for a year or two before I started visiting her. I went once a week, I went to all the Christmas parties and other social events. I also facilitated visits with her child up to a week at a time, a couple of times a year. I did this for about 11 years.
It did change me. The first time I went to a social, I couldn't tell the difference between inmates and visitors, and though I like to think I was non-judgemental at the time, it made me realize that I had indeed judged, otherwise I would not have expected to see a difference. It was a deeper learning that we are all the same, we all deserve to be there. "They" just happened to get caught. I learned the meaning of grace. The first time I drove to the prison for my first stay in the family visit house, the meaning of "Grace Alone" (Maranatha) became very real, very deep, and gave a whole new perspective to how there is no such thing as justice without grace and mercy. Every time I spend 5-6 days in there, I understood a little more of the social factors that contribute to how and why people end up in there, and each time I came out humbled that it could have been me in there. Not that I have broken any laws that would require a federal sentence, but the Bible tells me that even hating someone makes me as guilty as murdering them (1John 3:15). I belong in there because my heart has held hatred - even momentary hatred. By his mercy, by his grace, I am not in there. There is real humility knowing that we are all alike, all in need of salvation.
I believe this experience has also given me a different sense of compassion for people who are marginalized, an understanding of what I can't possibly understand in my limited human brain about God's justice versus man's justice. There was a lot of learning around this time. It was a time of spiritual growth and meaning-making.