"Once you find you can't walk as far and as fast as you were able, life becomes more complicated"

In this quote, Robert Sheckley is highlighting the idea that as we age, our physical capabilities might decline, making everyday jobs more difficult. The phrase "can't walk as far and as quick as you were able" suggests a reduction in movement and endurance. This can result in a sense of frustration and difficulty in browsing life. Sheckley implies that this modification in physical capability can complicate our lives, as we may need to change our regimens and make accommodations. It functions as a tip to value our physical abilities while we have them and to adapt to any changes that might feature age.