Walking Eevee 10km
I know I need to evolve during the day for Espeon (already used the name trick), but which hours are considered "day" and what timezone does Niantic use?
Anything else that I should take note? If I reach 10km during the night, what should I do? Keep Eevee as my buddy until daytime (wasting the extra distance since I have no need for Eevee candy)? Will I still get Espeon if I switch to Larvitar for the night, then during daytime, switch back to the same Eevee before evolving it?
Answers
Once you've walked 10km, you can switch out buddies. However, the eevee must be your buddy when you evolve it because you must evolve it from the buddy screen. Also, you must have good reception when your evolve so that the game for sure recognizes that it's daytime. And I always restart my game before evolving just to be sure.
I would say, unless you plan on doing a lot of walking through the night, just keep it as your buddy and walk a bit extra.
Following all of that, I'm 5/5 evolving espeons without the name trick.
Doing it from the buddy screen is not a requirement.
Walking 5km + 5km for two candies and evolving while it is your buddy. It is recommended for simplicity to just walk 10km consecutively, but you can switch buddies after 5km and later switch back to complete the 10km. (Events that mess with buddy distance do not shorten the required distance for Eevee's buddy evolution.)
You can change buddies after the 10km is walked, but you have to make the Eevee your buddy again before evolving it.
People have reported that trouble with GPS can interfere with the buddy evolution and result in one of the original three Eeveelutions.