Pokemon-go – How many candies do you get for every 2k, 5k, and 10k egg

Eggs come in three distances: 2km (1.2mi), 5km (3.1mi), and 10km (6.2mi). The distribution of these seems to be relatively random, however 5km seems to be somewhat more common than the others. 10km seems to be somewhat rarer for now, however these numbers have become extremely balanced since the beta.

Pokemon's strength (and rarity) is usually determined by the distance you need to walk to hatch the Egg.

You can get any non-legendary (and egg-grouped Pokemon) from eggs, although some are rarer than others. For instance, you're much more likely to get a Rattata than a Growlithe from an egg.

They expire when used 3 times regardless of the egg. So basically you only have two options:

• Hatch everything with anything:
  • Fast and expensive due to incubators expiring faster.
  • Good for mass hatching to increase chances for 10 km eggs.
  • Just make sure you don't hatch 2 km eggs with a limited incubator when your unlimited one is still available. Use that one first.
    
• Hatch 2 km eggs only with the unlimited incubator:
  • This saves incubator time, but eggs are hatched slower.
  • Better chances to hatch decent Pokémon due to the nature of sitting on more 5 km eggs.

Both ways have their pros and cons.

I don't hatch 2 km eggs with limited incubators (and with the unlimited one only 2 km eggs to make room for new eggs for a 10 km chance), because they're just too rare to waste them on Pidgeys.
If you're aiming for 10 km eggs and you have enough Pokéstops around to refill your egg collection it's better to use your incubators for all kind of eggs, preferably 2 km eggs due to their faster hatch time. This is of course more expensive, but a lot faster as well.