How often should transmission fluid be changed?

[N-OS X-tasy!]

Ammo wrote:
[quote=N-OS X-tasy!]
Check your owner's manual. I really don't know why you didn't consider that option before posting your question here.

I may be wrong, but I figure service intervals listed in owner's manuals are usually going to be pretty conservative in order to limit the manufacturer's liability and to generate sales for dealership service departments.
Implied in your statement is that you know better than the manufacturer what the service interval should be.

As noted above, service manuals typically have two service interval schedules, one for normal driving conditions and one for heavy duty driving conditions.