Generous, but not too generous. Clean out any old grease, wipe the cups and the spindle clean, then put a coating of grease in the cups--enough so that when you stick the bearing balls into the grease they're about half covered. It's a good idea to use new bearing balls. They're cheap--just a few bucks for the set. Then cover them with another thin layer. I like to do that by greasing the bearing surfaces on the spindle. Reassemble and adjust. Don't forget to replace the plastic sleeve.