Don't forget: someone totally unprepared, deceitful and incompetent will always blame his predecessor, the Congress, climate change, ISIS, etc etc And will never accept responsibility for anything he did or did not do. So, that's, imo, the answer to the question posted in this thread. "Never, no way, nada, zip, I'm black and you can't touch me, because if you did that would make you a racist." Unfortunately, he finds many who will support him, because their goal deep down is not to help the country but grab someone else's stuff.
Obama has been at worst a neutral strength president, and an argument could be made that Republicans haven't allowed many of his policy decisions to go into practice. Blaming him for the mess he inherited is not fair. And he gets a lot of flak because he's black and has a different ethnic background; most of America is progressive enough to understand that this is not an issue, but there remains a small minority of generally racist people who are very vocal about their ignorance. So we hear them, the P&R section is full of these people.
Americans have only themselves to blame for increased unemployment, lower house prices ( for some ), higher taxes, the subprime disaster, crime issues, and the prospect of higher social program costs in the years to come. For example, you elected George W. twice ( some others not impressive either, but he symbolizes the worst your system has ever produced ), you allowed your country to funnel most of it's wealth to the richest 1%, and you under payed on taxes and social programs for possibly decades. The true cost of all of these decisions will occur now. Most of the complaints some of you have is in fact the "blame game", and a refusal to understand the real new reality of what the US is. It's still one of most prosperous countries in the world, but it's got plenty of company in that regard now. Life in the US will not be as easy for the middle class, and no current President or even the next couple of them will change that. Your kids may legitimately end up paying for baby boomers mistakes.
Do not claim I am Democrat or liberal or try to label me. I'm Canadian, I have a true outsider view on these issues in the US, and have no advantage to take a position except on the basis of global harmony and well being. On that front, Obama has been better then many recent US presidents. Maybe not fully to the degree I'd like, but I suspect the two party system and constant deadlocks makes evaluating what can be done difficult. Policies tend to become watered down to appease the other party involved.
The question of "When is it Obama's fault ?" is not the right question. Almost every major issue in the US existed before he came to power, and the major recession / depression that some predicted was averted with strong, decisive monetary policy. Given time, his legacy won't be bad at all, it might seem underwhelming, but guys like George W. will be infamous forever. And I wonder if Americans understand how truly hated George and his political buddies outside of the US ? Obama has restored some faith in Americans. Perhaps you are expecting far too much from him given the cards he was dealt.