So, I'm a fairly big supporter of interval running. Running for the entirety of a 30 minute workout is just a little much for my knees and side. Until recently I had a bike to ride for longer workouts, something that is rather easy on knees. Since then I've instead been walking and running in intervals. At least it allows for more aerobics and calories than a regular walk.
Intervals are also the way to start running. One can't expect to go from couch potato one day to marathon runner the next. You could also use it when getting back into running after either an injury or a long time away from running.
In fact, intervals is how I started running in the first place. I began with 1 minute of jogging and several minutes of walking (meaning 4 or more), then repeated until the distance or time I wanted to go was up. With each trip to the park, I added more time to the jogging interval, took away time from the walking interval. Eventually, I was up to a full workout of jogging alone.
Now, the usual way to go about doing something like intervals of walking and running is with some sort of timer or stop watch. But, really, I just find that a bit annoying to concentrate on while running. Plus, I often do this with my nearly 60 lbs energetic lab, which makes looking at even a watch fairly difficult.
So, these days I use landmarks instead of time. Since I often run the same route I've picked out landmarks and push myself to get to it before I stop running. Since I've started back at walking & running I've added in more intervals of running, and I've moved forward my landmarks so I'm running farther with each interval. I suppose the important part is pushing myself, making myself run until I have gone as far as possible with that interval. It's the same concept of using time, just don't give up early.
Perhaps over time, I'll be back to a full 30 minutes of jogging. My guess, it's not something I really have in me anymore, but if I can get still get good exercise with only mostly jogging, then I'll manage with that.