GAW, I buy the bagged lettuce (w/ hechsher) and don’t check. But when I buy a head of lettuce, I always check every leaf.
Things like that are leniencies. Its fine, it just needs to be acknowledged.
The only thing I currently am very careful about is Tuna (we only buy Tuna with a mashgiach tmidi). There were a few other things that my family does that I’ve totally forgotten about because they didn’t affect me. I never bought those products. I probably should find out just in case.