The five-second rule in classic WoW is the pause in Spirit regeneration after a spell that costs mana; it is five seconds from the end of the cast.
no regeneration from Spirit for 5 seconds after a spell that costs mana finishes casting
"mana per 5" from gear is not affected
talents such as Meditation, Reflection, Innervate let a share of the Spirit regeneration through
Spirit works only in the gaps: stop casting for more than five seconds and the ticks start again. A caster who never stops gets nothing from Spirit, which is why mana-per-5 gear is compared at full value and Spirit at the share of the fight spent not casting.
| Priest, 300 Spirit, Meditation (15% through the rule), casting without pause | 0.15 × 88 = 13.2 per tick = 33 per 5 seconds |
| Same Priest, half the fight outside the rule | 0.5 × 220 + 0.5 × 33 = 126.5 per 5 seconds |
Last checked: unverified against Forever. These are the long-established values of the classic ruleset (the 1.x game of 2005-2006); World of Warcraft Forever is in beta and may differ. When you test this one in Forever, post your numbers in Theorycraft.