Now that effect Expiry cannot be used on lesser & charged items as per errata, this is the 1st campaign we allow it and I got a few unclear things to clarify 
1 - When it expires, can you reinvest it without having to re-invest the Vim vis?
2 - If the Vim vis is also expired, does it still occupy space or is the Item free of it?
3 - Can it apply to familiar bond effects?
Thanks for the help in advance
W
1 - Yes, you'll need to reinvest the Vis
2 - I'd say the item is free of it
3 - I don't see why a Magi would bother investing a Familiar Bond effect with Expiry, but sure, technically, you apparently can.
3 - Can it apply to familiar bond effects?
No.
All of it or just the part that is invested as expiring?
I'm still not being clear... let me try with an exemple.
Item is opened with 10 vim vis (No expiry)
Item is invested with 5 Corpus vis effect (no expiry)
Item is invested with 5 Auram vis effect (expiry modifier)
At expiry, do you need to use 5 Auram vis to re-empower the effect or you need one season to add back Some Vim vis & another to re-invest the Auram effect.
Also, I think the expiry clock only starts the 1st time you use the effect so you could have an empowered effect with expiry in the object that is kept there for a long time until it is needed...
W
The Expiry in that case will only apply to the effect invested, so you just need the time and Vis to reinvest the effect.
The opening doesn't expire, just the effect. So you can re-install the effect without re-opening. You will of course need the appropriate vis to re-install the effect.
see 1
ArM5 p. 99 reads, "Effect Expiry cannot be applied to Lesser Enchanted Items or Charged Items."
p. 105 reads, "the rules are the same as those for investing a power in an invested device, with five exceptions."
The exceptions don't include "no expiry," so I would say you can use Expiry on a Familiar Bond effect.
However, there might be relationship consequences ... How would your spouse feel if you bought a wedding ring with an expiration date?
Lol. I see it more as renting a cottage on Paradise Island for summer or renting a luxury car for a one year lease. She will appreciate both but I get your point.. she will want a repeat in the near future 
W
And the Lab Text for the effect expiry does you no good when doing it permanently. Because using a Lab Text you need to repeat the exact same procedure.
I am not sure I understand this. You open a greater enchanted device to enchantment using Vim vis; this vis never expires. Then, you place various enchantments in the device, using additional vis of the appropriate Arts. While it's not 100% clear from the text, we assume that an expired enchantment is still "there but non-operational" - so it occupies "vis space", it can be investigated in the lab, and it assists further enchantments with the same Technique or Form.
Sure, and it can actually be a good strategy to gain for yourself and your familiar a strong power early on in your magical career. A few decades later, when your magical puissance has increased, you can re-enchant the power if you are both still around and the power is still needed (I suspect many familiar enchantments were created with effect expiry at the beginning of the Schism War, and not renewed after expiration).
Yes! This is explicit on p.99 of the core book:
Effect Expiry: It is possible to instill an effect which will only work for a limited period. This period is counted from the first use of the effect, not from its creation.
What are the arguments for/against this?
It is a pretty big flex to expiry if it still hogs the Vim vis capacity after expiry. Would even be better that the Invested Vim vis use for opening the object associated to the expiry effect would also expire but both be fully removed & allow new Vim vis to be added & the expiry effect to be re-instilled.
Options are:
A) Expired effect expires and fully frees the space it occupied so that it can be re-invested or replaced by another effect
B)Expired effect expires but still hogs the "Space" of the object, reducing the potential of the object
C) Expired effect expires taking with it the Vim vis on which it was sitting within the invested object. This prevents a Verdi from recycling the Vim vis but allows, if nothing is left, for the magi to re-open the invested object from scratch without having to dis-enchant it. It also allows a Talisman to simply spend the season to add back the lost Vim vis and re-instill an effect as if the expired effect had never been there.
If we build on the acceptance that the bond can support an expiry modification, then I find option A or B fit better. A would make it as useful as when present in a bond effect. B would be consistent as the bond has infinite capacity.
W
I think the main argument is the specific text for effect expiry:
It is possible to instill an effect which will only work for a limited period.
It "only work[s]" until this time period ends. This very much has the feel of a broken-down car or similar. It's not like when a car ceases to work all the metal and other parts are suddenly magically recycled and the car no longer occupies any space in the world. Now, you may well be able to recycle your magic item (Verditius smelting) just like you could take take the broken-down car apart for useful scraps.
Of course, this is never made explicit, and you could play it either way. But I'm leaning away from interpreting "only work[s]" as "only exist[s]."
Using this analogy, can you tow the broken-down car and use your parking space for the new car?
If not, makes the expiry option pretty bad for Talismans as it puts junks in your premium heated garage that your can't remove. For regular invested devices, it makes it a costly choice but could still be worth it to push some effect beyond what your Magi would be able to do. Best option seems to be familiar bond but you're limited to effects that target you and/or familiar. Still add a lot to the value of the familiar bond.
Typically I would see stigmata from Verdi Magi who see this as terrible waste and very unsavoury use of their art. I can also see some familiars requiring you to spend the time and vis to restore the effect when it expires.
I think there isn't much in the way of rules to clarify if expiry occupies the space still after expiry or not. Troupes need to chose if they prefer having young magi push their limits at high cost more or not. A PoF with expiry in an invested item can push the power level/age of a magi by quite a bit...
W
I wouldn't allow the space used for expired effects to be reused.
The expiry option is not there to create reusable items. It is for items with a "Best before" date.
Either because you only plan to need the item for a specific usage. (For example, a dragon-slaying device that you won't need once the dragon is dead.)
Or when you create an item for some mundanes, and don't want them to have it for century after century. Better have the item stop working after a time - then you don't have to worry about it afterwards.
Using the expiry option with a regular talisman would be stupid. Don't do that.
Sure. So you're saying you toss away the item and replace it with a totally new item. I don't see a problem with this analogy.
Well, Talimans you can increase the space, and you might not need all that space for effects. Certainly, I find after a while I don't tend to go near filling them. So it might not be so bad for Talismans.
Sure, but I see this as advantageous. Instead of waiting for a while for a mediocre effect, we'll get a great effect now and then an even better one when that runs out. Win-win.
Right... but it would to re-instill the same expiry effect but it seems it be of limited use until you have very high lab totals and just looking for crazy penetration numbers.
Lab Total 50 in CrIg: PoF 20 +5 24 uses/day, +20 Pen, Expiry x10. Instilled in 1 season instead of 10
Lab Total 100 in CrIg: PoF 20 +5 24 uses/day, +70 Pen, Expiry x10. Instilled in 2 season instead of 20 or in one season with a lab text.
But you could also go reasonable and render the labtext useless.
Lab Total 100 in CrIg: PoF 20 +5 24 uses/day, +65 Pen, Expiry x10. Instilled in 1 season instead of 10
Let us not forget the initial season & Vim vis required to open the invested object.
W
As callen said, "it is possible to instill an effect which will only work for a limited period" (strongly) suggests that what you get differs from a "normal" enchantment only in that it will work for a limited period. Outside of this period, it still has all other properties of a "normal" enchantment, but simply does not work.
Of course, if you are an immortal magus, or you have Inscription upon the Soul, your talisman has unlimited space Furthermore, I think it would be reasonable to have a T:Part version of the Disenchant Ritual that only removes a specific enchantment that you know well (by having instilled it, or investigated it in the lab).
T:Part only works on physical parts of something. So it can't be used to target for example a part of someone's mind, or just part of the enchantments in an item.
I know what you're looking at, with
This target refers to spatial parts, parts that you could, at least in theory, cut off and put in a bag.
But we also have things like The Captive Voice (ArM5 p.147), that uses Part to take their voice rather than all the sounds they make, and Embrace of Boethius (HoH:MC p.119), that uses Part to take only a portion of the understanding of magic rather than all of it.