When I had my tie rod ends replaced I had the shop put in ones with grease fittings. Now I have a bunch of questions about it. What kind of grease should I use- regular chassis grease? When should I grease them... when they look dry or is that too late? Can you over-grease them?
I grease mine everytime I change my oil. Just use a brand name Lithium based multipurpose grease and you'll be fine. You could plug it with the fancy expensive stuff if you'd like, but it's not going to make them perform any better or last any longer.
It wont hurt anything to grease every oil change, probably a good idea in fact. And like gearbanger said, a Lithium base multi-purpose chassis greas will work perfectly