Don't walk with Chansey now. There are speculations that the Xmas event will have the 4x buddy thing again which mean you have to walk only 1.25km to get a candy I have already a list with which pokemons i'm going to walk.
Finish my Charizard
Vulpix needs 6
Koffing need 30
Abra needs 60
Grimer need 41
and then i will walk with Chansey
oh sweet, thanks. I've been walking chancey for 2 weeks now and im still not even at 10km
I'm playing this game for 40 days and i'm already past 200km with my Charmander I'm about to get my second Charizard already lol
fitness goals! i got charzards for days thoo cuz there was a local nest spamming them like crazy
im at 300km, combined, for both snorlax and dragonite. i havent really been walking anything else
I have already a list with which pokemons i'm going to walk.
Let me change the title to PokemonGo new pokemons coming 
I'm about to get my second Charizard already lol