I had occasional issues with saddle sores in the past, and found that cleanliness was next to Godliness in keeping them at bay. But on very long, multi-day rides they are harder to avoid. I found that padded shorts, while great for a few hours per day, are not so great for longer and frequent rides. They need to be washed after each ride, take time to dry, and such frequent washing slowly disintegrates them. You need at least a couple pair to rotate. A few years ago I gave up on padded shorts altogether. I started using Brooks B17 saddles, and found these great for all day rides with ordinary shorts, or even in jeans. I often go on long bikepacking trips, lots of hours each day, every day, and saddle sores can be a big issue. But unpadded shorts with cotton or merino wool underwear, with the aforementioned B17 saddle allow me to ride 8 to 10 (or more) hours per day in comfort, without getting saddle sores. Ordinary underwear and unpadded shorts are cheap, easy to wash, and quick to dry. I generally wear touring and MTB shorts by Pearl Izumi and Rapha, but Aere Tech makes good, unpadded lycra shorts.