Well basically to succeed in life you need to be able to live. It depends what country you live in when it comes down to being able to live, since if you live in a country like England the government will support you to a certain extent, in terms of being able to claim benefit money and housing you and to give you enough means to live by, even if it is a small amount of money it's free and enough to buy food, whereas in a 3rd world country it's more dog eat dog and every man for themselves, so you'll need to do more to survive.
So if you ever get to a point where you yourself are unable to survive, and by this I mean you cannot obtain food, or somewhere warm to sleep at night when it gets cold to prevent getting ill, you are failing in my eyes because by doing this you're likely to die, and by dying you have failed.
But then you may want to set goals for yourself and not achieving these goals can cause someone to believe they've failed. Not being able to afford that expensive sports car, or own that big house, or have that beautiful wife with healthy children may be a fail to someone whereas just having a car, a house, a wife and children may be perfectly acceptable to another. Or even just being able to get by each day and live til an old age is enough to keep some people happy.
So really, you can't really 'fail' life. You just live, then you die.