In Ingress, if I hack a portal at 3pm, do I need to hack the next portal before 3pm the following day if I want to keep my current hacking streak (for the Sojourner badge) alive?
TLDR; No, not necessarily.
I know, this contradicts the official answer from NIA as cited in What is the logic behind the timer of the Sojourner Badge? (and posted here), but this has been tested IRL.
Observations: I have, on two occasions, made a hack on Friday afternoon at 3-4pm, and the next hack on Saturday evening at 8-9pm. In both cases, I've kept my current hacking streak alive.
My theory: The interval you need to hack in depends on when you made your first hack in the current streak (and not your latest hack, as NIA states). For me, my first hack in this streak was at 6 am. This means that I had to make a hack between Friday 6 am - Saturday 5.59 am, and the next one between Saturday 6am - Sunday 5.59 am. As long as I make at least one hack during each period, I will keep the hacking streak alive. The fact that the particular Friday hacks were at 3-4 pm is irrelevant, they could have been made at 7 am or 2 pm as well.
This theory also fits with the experience people here and IRL have had, that the time their current hacking streak increases (or Sojourner badge is awarded) is different for everyone. For me, this happens early in the morning, likely at around 6 am.
Q: Sojourner isn’t counted once every 24 hours?
A: No, it isn’t. There were people who felt it would be a shame to cut off the counter at exactly 24 hours, so we left a bit of wiggle room. I cannot give you the details, but it is definitely not counted in periods of 24 hours. You do have a little room to play with. (Actually it is quite a lot… I can’t say a little).
This strongly supports HenricF's answer.
(Aside: the interview also debunks a whole load of myths about Ingress and gives the first explanation of stickiness of portal mods that I've seen. It's definitely worth a read if you're an Ingress player).
Yes, that's the official description.
Greetings Agents, there have been some questions on how the Sojourner medal works, so we decided to create a quick overview:
The medal tracks the longest streak of consecutive 24 hour periods in which you have hacked a Portal.
To keep this streak active, you must hack at least one Portal every 24 hours. If you hack at 10:00 AM one day, then you’ll need to do a hack by 10:00 AM the next day to keep the streak alive.
The 24 hour counter starts over every time you hack a Portal. If you hack at 10:00 AM, then again at 3:00 PM, you have until 3:00 PM the following day to hack again.
You may hack any Portal - it does not have to be the same Portal every time.
The stat shown as 'Consecutive Days Hacking' reflects your longest streak, not necessarily your current count (unless they are the same).
Though... I have no proof of it but I am quite sure that I extended the allowed time frame on one single day by some minutes and did not loos the streak.