Maybe the simplest strategy for staying out there the longest is to slow down. When returning to the walk (or run, or hike) from an injury, it is so tempting to notice how good you're feeling and then to push harder. But, if you have an old injury, you're better off to follow a structured plan of increasing distance and ignore the time. Or, walk for a designated time with very gradual increases each week and ignore the distance. Either way, you should go at a pace that is determined by you, not by the clock.
Maybe you're noticing that my message is to do less. It's true.
At every single training walk, someone has mentioned that they did too much the week before, and now they are hurting. My job as the coach is to reassure them that while we are on a schedule, we don't need to do more than what the schedule calls for: Some weeks we should do less. Even if we back off slightly, we will all comfortably finish the half marathon. If we push ourselves every week, we won't make it. We'll be on the couch with an ice pack.
So, go slow. Look at the elaborate summer gardens in your neighborhood. Smell the coffee as you pass the local roasters. But walk slowly, gently, quickly, smoothly, whatever suits your mood and nature. As you go, hang onto your sense of your comfort. It is your teacher, your guide, and your barometer. Learn to read it.
Sign up for a walking event.