Whilst enchanting.....

[Limper]

The equation for x/day items is (spell level x caster level x 1800/ 5 divided by number of times per day [x]) correct?

How do you determine what level a caster must be in order to enchant such an object?

 

[Quidam]

Well, the caster level required is based on the prerequisite spells for the individual item, not on how many times per day the item can be used. Bear in mind the caster levels listed in the DMG are "usual" caster levels, not minimum- and the caster level can be set anywhere between the minimum and the caster level of the one who knows the spell (in case you're accessing the spell through another caster or a scroll or somesuch).

Also, the # of times per day / 5 applies to all the various forms of item cost, not just the CL * SL * 1800. If you're going to be doing a significant amount of enchanting, getting Tome & Blood is a MUST, as the updated item ESTIMATION chart in the back is invaluable.