Familiar senses outside of a turn order

Question

Find Familiar says

as an action, you can see through your familiar's eyes and hear what it hears until the start of your next turn

What if you're not in a turn order, out of combat? When does this feature end?

To give a specific example:
In a dark passage, a Human carrying a Halfling could benefit from the Halfling seeing through the eyes of his familiar's darkvision? Or Devil's Sight for that matter. The Halfling could still guide the Human verbally. But there is no beginning of a "next turn" in this scenario. Does the link just remain until "turned off"? If this is the case, then why does it only last until the beginning of the "next turn" when there is a turn order? Wouldn't the connection just remain until "turned off"?

Answer 1

You can keep it up as long as you want

You generally can take actions you could take in combat or turn order also outside of combat, except for actual fighting.

The game (p. 189 PHB) defines rounds like this:

A round represents about 6 seconds in the game world. During a round, each participant in a battle takes a turn

So each round represents 6 seconds. Outside of combat, if there is no battle that requires turns, you can assume that actions that last until your next turn will last for 6 seconds.

The action to see through your familiars eyes is no different. You can keep it up as long as you like, chaining one 6-second use after the other. You just cannot take any other actions while you do so.

Answer 2

It can be kept on indefinitely

Rounds and turns are abstractions. Familiars allow you to sacrifice an "action" that you can perform in 6 seconds to see through your familiar's eyes within the same 6 seconds. Both in an out of combat, this means the same thing. You can keep seeing through your familiar's senses indefinitely apart from 6 second breaks you have to take in case you need your action for something else.

Its duration being until the start of your next turn means that you typically won't have your action to spend if you are currently seeing through the eyes of your familiar so you won't get to target someone using your familiar's vision for instance.

Answer 3

You can keep it going as long as you don't take any other Actions.

There's no limit on how long you can see through the senses of your Familiar, but while you're doing it, you can't take any other Actions. Most notably, this would mean you can't cast any spells with a casting time of 1 Action or longer, and no performing the Aid Another Action to grant Advantage to another PC's checks.