From a Quora post from November 2014.
Time does not exist. Only the illusion of time exists within a conscious observer (ie a time keeper).
To the conscious observer change of position within space creates the illusion of time. To model this, time is a function of a conscious observer, something moving, energy acting on this something moving and space for this something to move from one position to another position. Time is always the dependent variable. These factors create the illusion or perception of time. If time was real and moved, it would require or even would create energy, it does neither.
Unfortunately, our society's need and desire to over simplify processes commonly leads to time's misuse as an independent variable (i.e. x/bottom axis in graphs). This misrepresentation of time acting to "cause" phenomenon is taught and reinforced in our society almost everywhere. We are taught that time causes action. Time "causes" the recycling bin to overflow that needs to be taken out on Wednesday, my children to move to the next grade in school and us to get old. However, time causes nothing to happen, it is the byproduct of observable action. Of course, that does not negate the practical fact that the recycling goes out on Wednesday.
One comes to this question, "Does time exist?", perhaps in search of the fundamentals to their own existence. When I think about my life and it's "obvious" beginning and end, time becomes the perceived vehicle of my demise. If I intelligently deny time's existence then I also, in a way, deny my own possibility of non-existence.
While physics is commonly used to define time or defend its existence or not, this topic is more personal, psychological and philosophical than physical. Time is constructed by the conscious observer (you) and thus its existence or illusion of existence is only relevant to the you.