I tour where I am mostly in remote small rural towns. I seldom lock and never take my panniers with me on stops. I use a fairly cheap cable lock. I figure that in most of these towns people don't lock their houses or much of anything else even if they are away.
In larger towns I lock and am super careful where I leave the bike, but I am seldom in larger towns.
I ride an inexpensive bike and have mostly inexpensive gear. If push came to shove I could afford to replace all of it if I had to. I do keep the most theft worthy stuff in the handlebar bag which always goes with me.