Load your bag or Load your bike? Probably, another debatable question from my side.

When carrying items while riding, like water bottle, repair kits, pumps, or other stuffs that you might need, What is the best option.... to carry them?


On your cycle at saddle bag, handlebar bags, or pannier bags or etc. 
or, On backpacks, like hydrant pack, or simple travel pack.


While loading on cycle, it will increase the weight of the bike, thus affect a lot of things, like speed, traction, more reactive on corners. Like while using pannier bags.. it will increase rear weight, making it difficult on uphill. 

Also while loading on backpack, it will tire you down fast if its a big load, decreases your flexibility, agility &amp; etc.

So what is right way to do it?

Update:

The type of ride I generally, go to are commuting, mountain biking, &amp; trailing. And the items I generally carry are


Commuting: Water bottle(x2), Laptop (17"), books, copies, repair kits, hand pump, few other accessories.
Mountain Biking &amp; Trailing: Water bottle(x2), repair kits, extra tubes, hand pumps, candybars &amp; few other accessories
I divide between two extremes: 


Riding long distance with lots of stuff on good pavement: load the bike;
Riding short distance with not so much stuff and/or on rough road: load the back;


Of course, there are some additional considerations:


If the road is so harsh you must stand up to manoeuver (off-road, back-country, XC, etc.), load yourself. The bike suffers less (tires specially), and you can avoid falling from lost control;
If you have lots of gear and proper tires, loading the bike help to ride more stable and comfortable, since the cushioning effect of the tires (suspension) is enhanced by the added bicycle mass;
If you ride short, loading back is much more pratical. But if you are touring, loading the back becomes a huge source of discomfort and even health problems.


Tire choice is important, also. On a skinny-tire road bike, I would not feel safe or comfortable to put a rear rack in nothing but the smoothest of paved roads. In the other hand, I have already made loaded touring in roads that looked like the moon surface. How much is too skinny, or fat enough, depends on each person/bicycle/road.

In the end, the answer is "it depends", but I think the three (four?) parameters mentioned here are the most important about "what" it depends on, IMO.

Hope it helps.