A few holes in an established hosta and a seedling losing its only leaves are different problems. Both have been eaten, but the amount of remaining growth and the pace of damage change the decision. An insect on the plant might be feeding on it, hunting another insect or simply resting.

Begin with what is changing, how quickly and with what consequence? A garden supports plant-eaters, predators, decomposers and organisms that cause disease. You can tolerate some feeding while protecting a particularly vulnerable crop.

The aim is a response proportionate to the evidence. “Do nothing yet” should include a next check; “treat it” needs an identified problem and a suitable method. Neither a spotless leaf nor an abundance of wildlife proves that every plant is healthy.