Chains narrow as we add more speeds. Therefore 1 sp chains are the strongest, while 7,8,9,10,11 speed chains are each weaker than the previous because they are more narrow. Chains normally last about 1000 miles, however more narrow chains may need replacement with higher frequency. Masterlinks allow users to disassemble a chain without tools. This is important because chain tools weaken a link on the chain, making failure more likely. 

Lube is extremely important for chains. The original lube penetrates inside the links, so keep that for as long as possible. It is impossible to penetrate the links to the same level. Otherwise there are many quality lubes in the market. Local bike shops will be able to recommend something for your environment ( desert, rainforest, etc ).

Make sure to get a masterlink chain and lube it often. We use masterlinks on all of our 9 & 10 speed chains.