For short distances (e.g. up to 10km or 15km) most of us regular runners can do without drinking. But it is a healthier to hydrate yourself even for those shorter distances.
As for longer distance beyond 15km or 20km, most of us definitely will start to think of how and where to drink to stay hydrated. When I decided to join a full 42km marathon, I started to think about how and where to stay hydrate along my long distance training routes.
I started my long distance training runs with a 750ml Adidas bottle (about S$10) , carrying it with my hand while running. It worked ok for distance of up to about 20km. Beyond that distance I find that I will need more than 750ml of fluid in-take. And I wanted to concentrate on the run and the surroundings, not having to carry water bottle on my hand.
At the end I bought the NATHAN Speed-4 hydration belt (about S$69) that can carry 4 bottles of 10oz (295ml) each. It has a small pouch in front which is good enough to carry your car/home keys or a packet of energy gel. It also has a larger pouch at the back which can carry your handphone and up to 4 to 5 packs of energy gel.
During my first trial with it for 20km training run, I felt slight pain on both my left and right waist area near the front. It was due to the 2 bottles at the front bouncing up and down and hitting those areas. But no pain at the back of my waist. Was a little regret after that first trial and thought I should have bought one that carry just 2 bottles at the back instead. On my 2nd use and beyond, I do not feel any pain around the waist area. My guess is probably my body has adjusted and get used to it. And having 4 bottles are definitely better than 2 during long distance runs of more than 20km. You will need that.
During my first 42km marathon race I carried the belt with me but with just 2 bottles as there are hydration points along the racing route. I used the belt mainly to carry my car key, handphone and 4 packs of energy gel.
The bottle has tilted neck to make the drinking easier while running. The belt that I bought uses velco attachment which I preferred as it is still adjustable for changing waist size.
For those who are interested in getting a hydration belt, the popular ones are Nathan and FuelBelt.