The last time I did the math, I figured out that my dogs and I have gone on more than 14,325 walks over the years. Here’s what I’ve come to value during the miles we’ve covered.
1. A leather leash. Especially for medium to large dogs, I recommend leather over just about any other material. It’s not only soft on your hands, it’s strong (even the best-trained dog will sometimes threaten to pull you off your feet—squirrel, anyone?). A well-made leather leash will last your dog’s lifetime (see examples at Paco Collars  and Bridgeport Equipment .
2. Treats. Small, easily digestible varieties like Pet Greens  or other jerky-like treats that can be broken into small pieces are popular with our dogs. Kibble morsels also work well.
3. Water and a collapsible water bowl. Itzadog’s  Zuka bowls are great. For eco- and safety reasons, I prefer a reusable water container that I carry in a sling; aluminum water bottles are lightweight, and a bota bag  also works.
4. Plenty of pick-up bags. I always carry more than I think I’ll need, and a paper towel or two.
5. Pockets—the more the merrier! I like jackets with big roomy pockets, and sometimes cargo pants, which provide even more carrying capacity. If it’s too hot for a jacket, a multi-pocket dog-walker’s belt is a good alternative; the DOOG Walkie Belt  is a stylish new model.
6. A small flashlight. Makes finding things—like poop deposited under a bush—much easier, especially on those early-morning or after-dark outings. I have a tiny one attached to my jacket’s zipper tab.
7. A whistle. The Fox-40  produces a super-loud sound that carries even in windy conditions. Good not only to get your dog’s attention (be sure to train a recall using it), but also for your own personal safety—it’s a great alert.
8. Comfortable footwear. Without a doubt, warm, dry and well-supported feet add light years to the experience; during the rainy season, I go for waterproof/water-resistant materials. (Take a tip from hikers and get the best socks and shoes or boots you can manage.)