Enchantments (Technical)

There are two types of enchantments:

• those which affect how the object interacts with the world (object-affecting),
• and those which affect how the object's user interacts with the world (wielder-affecting).

In both cases, the enchanter (the caster) imbibes the enchanted item (the object) with energy that thus provides the object with a given property. This may be magical or non-magical. This property will be maintained until the energy dissipates or is otherwise expelled in full, at which point, the object will return to its original form.
Enchantments which require activation (most common with wielder-affecting enchantments) will maintain their energy until they are activated. However, they expel energy much faster than "passive" enchantments. When and the rate at which an enchantment's energy will dissipate is dictated by the type of enchantment, following a rough scale as follows:

Longer
Passive + self-restoring (Royal Weapons)
Passive + weak (water/fireproofing)
Active + weak (household magic)
Passive + medium (underwater instruments_A)
Active + medium (self-moving tools_B)
Passive + strong (magical tools)
Active + strong (Crowns1)
Shorter

(It should be noted that in these descriptions, explicit use of 'magic'/'magical' as a descriptor implies something where the energy itself may be adding on a part, or allowing an inanimate object to react to its environment_C. In all other cases, the effect itself is nonmagical, and the energy, or 'magic', is simply a metaphorical engine.)
As you can see, the strength of the effect is much more telling than whether the enchantment is "passive" or "active". There is very little mentioned here about "wielder-affecting" enchantments, so as not to confound the general trend. However, it is to be noted that wielder-affecting enchantments, unless constantly restored, will lose efficacy within days of active use. Despite this, most would be considered "weak" or of "medium" strength in comparison to their object-affecting cousins.
In a similar vein, the seeming back-and-forth between longevity between passive and active enchantments based on strength is a slight misnomer. There are very few truly 'active' enchantments which are not considerably stronger than their passive equivalents, and thus active enchantments are somewhat skewed towards being shorter in length. Meanwhile, most seemingly 'passive' enchantments of strength are actually 'active', notably in the realm on enchanted bandages. Many stronger object-affecting enchantments have a sort of "on-off" switch, allowing their energy to be saved for when it is strictly necessary. In this sense, they are not truly passive, as they require activation, even while their effects at a lower strength may be enchanted using a passive enchantment.
Moving on.
While this rough layout assumes that the same amount of energy is used for each type of enchantment, this is rarely the case. Though some passive and weak enchantments are performed for the long-term (particularly with 'proofing something for preservation), most household and 'everyday' enchantments are casted for a short-term effect. Ironically, most "high-energy" enchantments, those which would last the least amount of time, are generally designed for long-term affect.
In this sense, you will find that enchantments fall into three categories of longevity, strength, and type:

• short, weak, and object-affecting,
• long-lasting, medium-power, and object-affecting,
• or long-lasting, strong, and wielder-affecting.

The first and second types are more common, while the third is reserved predominantly for royalty or for the magic which Life employs in her own home2. There are of course exceptions, with the Royal Weapons mentioned earlier as a strong example of a strong, passive, object-affecting type of enchantment, but for a simplified version, this summarizes most enchantments well.

For details on what all this means when translated into reality, and for convenience to avoid technicals, the details of the specific effects are on this page.

Manifestation

A "underwater instruments" :

Aided by the waves, flutes surrounded in their own pockets of air join strings as carefully enchanted to be protected with air as they are carefully tuned. The ocean current distorting chords, notes wobble and wash in etudes unheard in strict air; where they move from the air to the water, they slow and speed, simple wood and metal tunes translated into something that is truly different from anything on Earth.

B "self-moving tools" :

Needles and pins dip in and out of fabric, thoughtful in how they hold and weave through the clothing on the model. Better than tailor fit, they will certainly make it hug close to your figure; despite how close they prod, though, these are sharpened points that will never prick skin.

C "an inanimate object (reacting) to its environment":

Fine china breaks against wooden floors, but these teacups learn to slow themselves before touching down; if indistinguishable at a glance, they are safer against the hard stone floors, and with a little extra, might save your drink from gravity, too.

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1 " Crowns " (linked in list): the one example drawn from wielder-affecting types of enchantments, as there are few other examples of such grandiose scale. Check linked page for details.
2 "the magic which Life employs in her own home": in nearly all cases, Life herself is a direct source of energy for any enchantments or other types of magic which she directly practices. While some of them would be sustained without her, most would run short of energy and lose power within short time of her passing.