A few other questions remain to be answered even after you've established that a character can activate an item.
Items with Limited Uses
Many items don't work all the time but instead work only a certain number of times or a certain number of times each day, week, or other time period.
Charged Items: Items such as wands and staffs hold only a specific number of charges. Once those charges are used up, the item becomes inert and nonmagical. Most charged items are activated with a spell trigger or a command (see Part Two), and they usually can function only once a round because it takes a standard action to activate them. Some charged items work automatically, expending their power whenever needed (a brooch of shielding for example) and they work as often as needed so long as their charges haven't run out.
Uses Per Day: Other items work only a certain number of times each day; for example, most rods fall into this category. The rules don't bother defining a "day" for you, and most of us can figure that out on our own. If it ever becomes important, treat a "day" as any contiguous period of 24 hours. There is no set "recharge" time for a magic item. Instead, the item functions a set number of times in any given period of 24 hours. For example, a rod of enemy detection works three times a day. You cannot activate the rod three times starting at 11 PM one day, then activate it three more times starting 2 hours later (at 1 AM the next day). Instead, you can activate the rod up to three times during any period of 24 consecutive hours. If you activate the rod at 11 PM on a given day, you can activate it only twice more during the following 24 hours. Let's say you activate the rod again at 1 AM the next day and again at 7 AM that same day. You have exhausted your daily limit of activating the rod ability at 7 AM. The earliest you can activate the rod again is 11 PM on the second day, when you can activate the rod only once (because you already have activated the rod twice during the preceding 24 hours). If you don't use the rod at all after 7 AM the second day, the earliest that you will have three activations available again will be 7 AM on the third day.
Once you exhaust an item's daily use limit, the item remains magical, it just won't function for awhile.
Use Limits for Other Time Periods: The foregoing applies to other items that have use cycles longer than a day. For example, if an item works only a few times a week, the use limit applies to any contiguous period of seven days (even if your game world doesn't use 7-day weeks).
Elapsed Time Limits: A few items work only for a certain total amount of time each day. For example, boots of speed work a maximum of 10 rounds each day. In most cases, the time you use such an item need not be continuous. For example, you can activate or deactivate boots of speed as many times as you like in a day, so long as the boots aren't activated for more than 10 rounds during one day (see the notes under Uses Per Day for a definition of a day). Such items are almost always command activated and it takes a standard action to activate or deactivate them (unless you simply allow the time limit on the item to run out).
Wearing Magic Items
As noted in Parts One and Two, some magic items must be worn on the body before they can function. Most such items work only when they're worn on a specific part of the body (sometimes called an item "slot") as noted on page 214 of the Dungeon Master's Guide. For example, you cannot wear a magic cloak or shirt on your head and expect the item to work. That said, it pays to remember that the game includes item slots mostly as a matter of convenience. The item slot rules, for example, help you decide if it's possible to wear magic gloves under magic gauntlets (if the gauntlets are roomy enough, there's no reason you can't wear gloves under them, but in the D&D game, you can wear only one pair of the two pairs of items.
The item slot rules also serves to keep characters from becoming overpowered (by wearing 10 rings, for example) and gives players an important resource to manage.
It's worth noting that the item location rules in the Dungeon Master's Guide assume a humanoid body. Nonhumanoid bodies have the same set of 12 item locations noted in the Dungeon Master's Guide, though perhaps in slightly different forms. You can find examples in the Draconomicon and in Wild Life, Part Two.
It's also worth noting here that a campaign can get along without using item slots at all, provided that the DM carefully controls the wealth the PCs have. For most campaigns, the wealth guidelines on page 135 in the Dungeon Master's Guide will suffice. If you follow those guidelines and you're careful to make sure that no single character has significantly more wealth than the all the others, you don't need to worry too much about overpowered characters. Of course, you'll still face arguments over how many items a character can wear on one part of the body.
When your campaign uses the item slot rules (as most do) you always can carry more items than you can wear in a particular slot. If you wear more items in a slot than will fit, only the first one (or the first two, in the case of rings) that you put on functions. As a rule of thumb, it takes two move actions to switch around items that you wear -- one to shed a functioning item and put it away, and one to get out the replacement item and put it on. That assumes that you keep the replacement item in some handy location, such as a belt pouch, and that you store the original item somewhere equally handy. Note that you can just drop an item as a free action, but that's for things you hold in your hand. Most items you wear are made to stay in place once you don them and it takes a little fiddling to get them off. Armor and shields have their own rules for donning and shedding (see Chapter 7 in the Player's Handbook).
Saving Throws Against Magic Items Effects
Some magic item descriptions include saving throw DCs for the effects they produce; however, they usually do so only when the item does something that doesn't correspond to a spell.
Most magic items produce spells or spell-like effects. For a saving throw against a spell or spell-like effect from a magic item, the Dungeon Master's Guide gives the following formula: the save DC is 10 + the level of the spell or effect + the ability modifier of the minimum ability score needed to cast that level of spell. As it happens, that formula works out to a DC 10 plus 1-1/2 times the spell level, as shown on the following table:
Save DCs for Spells or Spell-Like Effects from Magic Items
It's important to remember that the item, not the user, sets the save DCs for the item's spells or spell-like effects. In most cases, this means that the save DC for a spell from an item is almost always lower than it would be from a spellcaster.
Staffs are an exception to the rule. Calculate the saving throw DC just as if the wielder had cast the spell. If a staff user has an ability score lower than necessary to cast a spell stored in the staff, the character can still use the spell (provided that the character meets the requirements for using a spell trigger item; see Part Two), but the character still must use the lower ability modifier. As a house rule, you might want to allow a staff user to use his own ability modifier or the minimum modifier for the stored spell, whichever is higher.
If a staff user has a feat, item, or special ability that improves his spell save DCs, those also apply to spell the character uses from a staff. For example, if a character has the Spell Focus (evocation) feat, the save DC bonus from that feat applies to evocation spells the character uses from staffs.
Magic Items and Metamagic
When an item stores or duplicates a spell effect, the item user's metamagic feats (if any) don't apply to the spell. An item could produce a spell effect that has been modified with a metamagic feat, but only when the item was made that way in the first place. Such items are more expensive than items that store regular spells. You can see the effect of metamagic on item prices by looking at the prices of the wands shown in the Dungeon Master's Guide.
Likewise, other feats the item user has (such as the Spell Focus feat) do not affect spells produced from items. Staffs are an exception (see the previous section), but even a staff does not allow the user to apply metamagic feats to spell effects from the staff.
That just about covers magic items in play. Next week, we'll wrap up with a few odds and ends that we haven't yet covered.
About the Author
Skip Williams keeps busy with freelance projects for several different game companies and was the Sage of Dragon Magazine for 18 years. Skip is a co-designer of the D&D 3rd Edition game and the chief architect of the Monster Manual. When not devising swift and cruel deaths for player characters, Skip putters in his kitchen or garden (rabbits and deer are not Skip's friends) or works on repairing and improving the century-old farmhouse that he shares with his wife, Penny, and a growing menagerie of pets.