You can be lazy if you don't mind more suffering and taking longer. The issue with riding almost every day is that it's harder to recover. Five days a week is plenty, especially for older riders.
I think the most important moment of my randonneuring career was when I got to 200km on my first 300k. I realized I only had 100km and I felt fine. Plus, I was about to go downhill to a good diner, so it was a positive moment. When I got to the finish of my first 400k, the organizer told us that was the most important distance, because randonneuring events just build up 400km segments. But I was too tired to feel particularly positive about it. And my lights all failed, so that was bad.