all intents and purposes / all intensive purposes
The set phrase meaning “in every practical respect.”
Use for all intents and purposes. For all intensive purposes is a mishearing, not a variant. The phrase is already heavy; if in effect or in practice will do, use that.
Examples
UseThe old rule is, for all intents and purposes, dead.
AvoidThe old rule is, for all intensive purposes, dead.
PreferThe old rule is in effect dead.