normal yard and double that if your lawn is thin.
finally, if all of this seems like way too much work right now (or ever), then simply water the lawn a couple of inches a week when night temperatures stop getting below, say, 40 degrees. in two weeks it will green up. then, and only then, should you consider putting fertilizer on it -- as then and only then will you be able to tell if it needs it.
of course, this means you have to pay a bit of attention to your watering system. make sure your hoses do not leak from faucets or attachments. no one wants to get wet 