I think the common wisdom on the spline lubes is 15,000 to 20,000 miles. Every tire change, assuming 5-8,000 miles, would probably be excessive. But if you're so inclined then go for it.
The lube is known to creep. I guess if it didn't we wouldn't have to lube so often. Bruno, the guru of driveshaft/ final drive rebuilds, welds a plug into the new shaft to prevent creep. It's really not a complicated job. The right tools, a little know-how and the right attitude and you're good. Don't think you should have to replace the clutch pushrod, unless you bend it. That's where those nice long 8 mil bolts come in. F14, they just add a degree of safety to the tranny removal. Why risk it? The bolts are cheap.