i think you should set a future goal like a fitness level you would like to reach and then just keep your eyes on the prize.
I prefer walking; running is too high-impact for my old knees. Walking in very hilly areas is good, but walking on beach sand is even better. Dry sand if you're looking to work your leg muscles, wet sand if you're going for distance (I've walked over 10 miles non-stop on wet beach sand; too bad I don't live close enough to a beach to do this anymore). For those of you in cold climates like mine, what do you substitute for outdoor running/walking for the 6 months (or whatever) that the entire outdoors is covered in miserable, slippery ice?
I don't run as much as I should but when I do about 3 miles...I just find it really boring and when you're bored you notice things hurting
i run about 4 miles 4 times a week, but i do it in the fields next to my house so it is mmuch harder than normal, also doing it up hills is even better.
I used to run approx. 2-3 miles .... 3x per wk when I wasn't doing 3 hours of cardio (kickbox) classes per week. I tend to now run for enjoyment. Running in a light rain around a track by lake or in the sand along the shoreline while listening to my cd player.... or with the dog.