As others have said when you ask me to be your reference I'll be a reference for other opportunities than the immediate one unless I specifically say otherwise.
You can continue to use a person as a reference until such time they are no longer relevant or they explicitly ask you not to. You do not need to ask again unless you feel a specific case might make them uncomfortable. (IE let's say they HATE what Company X has done to the gaming market... and you're applying to Company X)
Notifying your reference
It's considered respectful to let your reference know in advance anytime you expect someone might call them. Now, there is some caveats here.
If you are pursuing several jobs you should probably call the reference just once and let them know they might get a call or two, and what sort of job you're pursuing. (That way they aren't caught by surprise and can do what they are prepared generally speaking)
If you are pursuing a specific job you should call your reference and give them what details might help them help you. If the company you're pursuing is hiring you leading a project let your reference know you'll be expected to lead a project. Then your reference can focus their details on your management, leadership skills, and attention to details.
Updating your references
References probably don't want you to constantly let them know the out come of every little job pursuit. (Unless your friends who like to talk about that sort of thing) That said, it's to wait until you land a job or stop looking than contact them only once to thank them.
Don't abuse references
Reference abuse is mostly when you know in advance you're going to do something your reference wouldn't be happy about. Job flipping, needless name dropping, ect. Your reference is someone helping you out, if you act unprofessionally it can make them look bad for referring you. This is one of the few ways to get a reference to demand you stop using them.