According to dialogue with Istirus, he and Jantus were adventurers before living in Bruma. When they grew older and retired, they moved to Bruma. Istirus claims that they are happy to live a peaceful, quiet life there.
Istirus will start his day at 6:00 AM, and spend the next several hours inside talking to his wife, before leaving the house at 9:00 AM. He will spend his day walking around town, mainly near the Great Chapel of Talos. At 4:00 PM, he will head to Olav's Tap and Tack for a two-hour lunch, before leaving the inn. At 9:00 PM, he will return to his house, and will eventually go to sleep at midnight.