Al - I grease all the wishbone pivot bearings twice a year, ditto halfshaft UJs. Top up grease in wheel bearings once a year.
My car sees about 4000 miles a year, so I guess this is overkill, but so is everything else I do on my cobra. The way I drive it, it is cheap insurance.
Rear end
oil I change every year, ditto gearbox.
One good thing to rememember when building up a jag rear end is to use the correct (angled) grease nipples on the outboard UJs - and angle them towards the car centreline - you can't get on the straight ones once they are buried in the hub carriers.
Once a year or more I check for play in all the elements of the rear end - wishbone pivots, UJs, hub/driveshaft splines - I found that it is almost impossible to get all the play out of a jag rear end, but now that I have a baseline.....
hth