A normal cloak, you wear it for a certain amount of years, and it becomes worn, ragged, and ready to be replaced. A magical cloak, enchanted with an effect that does not expire shouldn't fall apart that fast. Does it ever degrade? What about items with a lower 'shelf life,' like flowers or muffins? If a magus made a charged item out of a muffin, would the muffin stay magically fresh until it is eaten and the charge used up?
I'm just curious what other's opinions are on this.
if it was a more durable item like a cloak, then it could be repaired by a skilled craftsman without loss of power, magic food however, unless magically kept fresh (quite easy actually if I remember covenants right) would rot as normal.
or in my usual hand wave...if it makes a good story, then it will be an issue, if not, it's not an issue.
A
There's no provision for the item not degrading. I think that it should degrade. However rego craft magic can probably keep an item functional indefinitely.
[color=brown][i]We take you now, to a covenant, in Canoga Park...
The Muffin Mage... is seated... at the table in the laboratory of the Utility Muffin Research Kitchen... reaching for an over-sized chrome spoon he gathers an intimate quantity of dried muffin remnants and, brushing his scapular aside, procceds to dump these inside of his shirt...
He turns to us and speaks:[/i]
"Some people like perfect simulations better;
I, for one, care less for them!"
This falls into the category of "what's good for the story".
Do you have grogs who shovel out the privy? Does your wizard ever wake up to the use same in the middle of the night? How often does it "rain" in your saga... your Northern European or English climate saga? When was the last time a moth or beetle chewed on a non-protected library or lab text?...
Some things just do not add anything but headaches, depending on the players and the tone of the story they like to tell.
There are some spell effects that will constantly "heal" an item - a small CrHe spell on your staff-talisman is not a bad plan, for if it ever cracks or is chipped in battle, that could weaken it, and it's not something you'd want broken outright (and strikes me as an In-Character thing to do, and gives the SG an excuse ~not~ to have it break when every reasonable excuse says it should.)
There are some things that are just such a stretch of the imagination, so overtly inappropriate at face value, that they cry to be discouraged or punished. But if it's a classic, if it's colorful and creative and tells a good story... go with it.
[color=brown]/...the band steps forward again, and the music builds.../
Girl you thought he was a mage
But he was a muffin!...
Originally, I thought that making an item magical would convey some durability to the mundane object that held the magic. Upon further contimplation though, I wondered if my notions of item durability weren't just carried over from another gaming system. Hence, my questions.
But if magical tems wear and tear similar to their mundane counterparts, why would a magus enchant anything other than the most durable materials? Why would a magus spend a season enchanting a boot for travelling when the boot will wear out in a few years?
And thus the time-limited enchantments for just these applications. Good enough for a time.
If it is enchanted, then the effect is still good even if the muffin has gone stale 
The form of a boot is attractive because a boot can give a bonus to the effect, whereas a belt of running just doesn't cut it.
Also, a mage uses top-grade materials. Hardly explains a perma-boot, but it helps.
And if the mage is smart, the "soles" of the boot are not part of the enchantment, and can be replaced - something that no one bothers to mention, and so is handwaved. But that would be one explanation as to how they last "indefinitely".
In short - yeah, you're perfectly correct, and if you want to go there, and in effect limit magic items to practical and durable ones (or non-durable with the time-limit multiplier to create), there's no reason you can't do that. It doesn't affect the game so much- in fact, it moves it further from fantasy gibberish to Mythic Europe semi-reality and better suspension of disbelief - and I'm never against that.
But for those who want Wool Slippers of Toastiness that were made and used by Bonisagus himself and have been handed down and used over the centuries... meh, who's to say that's such a bad thing?
Creo Rituals to preserve or repair items, perhaps, used to keep such priceless artifacts as Bonisagus' Toasty Slipper in good repair?
I need to go there and make some yellow snow charged items in the covenant of St Berdino now.... 
Xavi
Well, Bonisagus would have made them as a fully integrated invested device, not a cheesy lesser device.
Altho' the slippers are "small" (size 2), they're probably made from wool from the golden fleece of Jason and the Argonauts or something, and so hold about 30 magnitudes of effects all told. (Including, hopefully, a PeIm based on smell).
Are you implying that invested devices, since you use vis to open them, are more durable?
... no.
Was just wondering. Didn't want to read too much and all.
In the bishop's staff by MdV there was a (major) magical hose that had one of its enchantments "prevent usual wear and tear due to usage". IIRC it was relatively high level, hiugher than what I but make it anyway. Still, something like that is likely to find its way into almost any major item worth its salt if the item is subject to wear and tear (swords, clothes....). Having the likes of Excalibur and Durendal (or their Hermetic equivalents), or a magical cloak be disenchanted because they wear away sounds odd, at least 
Cheers,
Xavi
[i]Do you know, the Muffin Mage, the Muffin Mage, the Muffin Mage?
Do you know the Muffin Mage? He lives in covenant "Via Drurus"[/i]
Lame, I know (not to mention it doesn't fit the meter)...but I couldn't resist!