How far do you actually have to walk to get the last .01 km on an egg?

I don't. I shamelessly exploit GPS drift by turning WiFi on and off lol

After an update a while ago which supposedly reduced egg/buddy distance gained due to GPS drift, I've never picked up less than 0.03km (30m) at a time. So if you walk less than that, you won't gain any distance.

It's less the distance that matters, and more the fact that it only updates the distance you've traveled once every few minutes. So yeah, it can be annoying when an egg stops at 4.99 out of 5 km, then you have to keep going for like 5 more minutes before it finally hatches.

I've had my buddy distance go up by as much as .5 km in the time it took to give me that last .01 for an egg, so all that extra distance just went to waste instead of contributing to the next egg.

...I love when that happens, because you find yourself walking what seems like forever wondering wtf, then you spot a dratini or something AND THEN the damn egg hatches -- usually with a stupid spinarack only after to find that the dratini has left.

It updates every 4 min.