The description of the find familiar spell states (emphasis mine):
You gain the service of a familiar, a spirit that takes an animal form you choose. [...]
As an action, you can temporarily dismiss your familiar. It disappears into a pocket dimension where it awaits your summons. Alternatively, you can dismiss it forever. As an action while it is temporarily dismissed, you can cause it to reappear in any unoccupied space within 30 feet of you.
Starting at 14th level, any creature that you summon or create with a conjuration spell has 30 temporary hit points.
And the rules for temporary hit points state, in part (emphasis mine):
Unless a feature that grants you temporary hit points has a duration, they last until they're depleted or you finish a long rest.
I'm not quoting the whole thing, but the description is written from the perspective of the creature that has the temp hit points, referring to that creature as "you" and "your".
Say a 14th-level Conjuration wizard casts find familiar. Since it is a conjuration spell, the familiar would get 30 temporary hit points. But how long do these temporary hit points last?
The description for THP says that if the feature that granted the THP has a duration (which it does not), they last until depleted; otherwise, the temporary hit points last until "you" finish a long rest. In this case, "you" is the familiar, and since the familiar is a spirit, it technically should not need a long rest. Therefore, it would last until depleted, correct?
Likewise, the feature says, "any creature that you summon". While the spell states that the familiar, if dismissed, waits in a pocket dimension for "your summons." Would this mean that every time you bring the familiar back from its pocket dimension, it gets a fresh batch of 30 THP? (And yes, I get there is more than one definition of "summon".)
I'm curious how to rule these situations.