30 minutes - 2 hours
My wifi was not working, it kept going in and out but not in a no service way it was turning itself completely off and you couldn't click it to turn the service back on. Restarting the computer worked for a while until it stopped coming back. I eventually got the error "no hardware installed" (bluetooth always worked though which is odd)
this was my first time doing a hardware repair myself and it was easy enough. I haven't had an issue since!
Don't spend $250+ at the mac store for something simple....