Integrating Spells & Magic Into Your Campaign (POSM)

Integrating Spells & Magic into Your Campaign Player's Option: Spells & Magic is designed principally as an expansion, not a replacement. However, there are a few special cases where the information presented here should be taken as an update and replacement of existing rules. Specifically, the wizard spell schools and priest spell spheres have been slightly rearranged to improve game balance and make the wizard and priest specialist classes more competitive with respect to the general versions of these characters, the mage and the cleric.
Most of the rest of this book can be integrated piecemeal into an existing campaign without any trouble. For example, additional proficiencies and new spells can be approved or disapproved by the DM on a case-by-case basis. These were designed to be completely usable with or without the Player's Option rules.
==Making the Switch==
Adding spells, magical items, or the critical hit rules to an existing campaign is fairly easy, but a DM may have trouble with some other material in this book. In particular, existing spellcasters may wish to take advantage of new class abilities or optional specializations that weren't available when the character was first created. There are several ways to handle this. First, there's no reason that a DM couldn't allow a player to "re-design" his character, incorporating the abilities he thinks his character should have had all along. If a PC cleric comes from a savage tribe and portrays himself as a barbarian, it's perfectly reasonable to allow him to rebuild his character as a shaman (see Chapter 2 ) and continue play. If the player is altering his character without any good rationale or explanation for why he's making the change, the DM can require the character to pay a penalty of 10% to 50% of his experience point total, depending on the DM's assessment of the scope of the alterations.
There are a couple of things a player should not be able to do by redesigning his character. A character shouldn't change specializations without a very good justification, so a necromancer shouldn't be rebuilt as an enchanter or wild mage, and a specialty priest of Lathander shouldn't become a priest of Helm. A character's basic ability scores, equipment, proficiencies, hit points, and general personality shouldn't change. If a player was playing a barbarian cleric correctly, he was probably choosing skills and weapons appropriate for a shaman—and if he wasn't selecting these skills, the reasoning behind the switch becomes much more suspect. Finally, a character shouldn't actually change classes or become dual-classed or multi-classed.
The Spell Point System: The most drastic change to the AD&D game lies in the new spell point system described in Chapter 6. Try running a brief "trial adventure" using the rules before incorporating them into your campaign. The spell point rules provide spellcasters with a lot more flexibility than the standard magic system without increasing their raw combat or spell power, but if PCs are allowed to make use of spell points, NPCs and monsters should be able to as well.