Comparing potions and armor that grants a stat bonus (like the Power Towers or the Dexhelm), it seems that consuming an object to gain the bonus results in a relative bonus, while equipping it results in an absolute bonus. What I mean by that is this: If a piece of armor grants 15 strength, it grants it to anybody, always. If a potion gives you that bonus, the amount of strength gained is related to the strength of the potion and the strength of your character. And the biggest difference is, of course, that potions only give the bonus temporarily.
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