Four year lag in policy impacts

In general, my rule of thumb when judging how well a President has governed is to wait 4 years and see what happened in the Presidential term immediately following the one being judged.  By this measure, George W. Bush's second term was a governing disaster because Obama had a difficult time in his first term dealing with the impacts of the housing bubble.  Obama's first term was a governing success because he had a generally easy time dealing with the economy in his second term, even if ISIS now became a threat after Obama withdrew from Iraq in his first term.  Similarly, Obama's second term was largely a governing success because Trump had an easy time for most of his first term, but now it's only taken a 3 year lag for Trump's governing problems to take hold or perhaps more accurately the mistakes of his pandemic response were a little unusual since it only took a very short time to be realized.

You can even go back further and say George W. Bush had a difficult second term because of the mistakes he made in the first term, mostly Iraq.  Whatever troubles George W. Bush had in his first term can be traced to the tech bubble in Clinton's second term and Clinton's inability to deal with Osama bin Laden (though he did try much harder than George W. Bush did before 9/11).  Clinton's second term was largely a success because of the efforts Clinton made in his first term to fix the economy and reduce the deficit.  Now, this rule of thumb is not perfect and the evaluations are a bit subjective, but in general it does take a few years for policy mistakes to rear their ugly head, so you do have to wait a little bit until you really know if someone has governed well or not, so overall I think it works pretty well.