well as to how long not sure but I know it will last for at least 5 hours because I have used it that long. and as to how to put it out. either blow it out or put some aluminum foil in the inside of the lid and just put the lid back on. It will go out on its on and the foil keeps the lid from melting. I have used these type heaters for years now. I have propane heaters but i prefer these. I keep a extra bottle of alcohol in the stand.