Is time empty of inherent existence? My understanding of dependent origination is that it asserts that all things are empty of inherent existence. On an intellectual level I can appreciate and accept this however I struggle when it comes to time. Is time included in this? Is it dependent on something else and if so what kind of things are conditions for time? In my mental picture of the world time is kind of a backdrop for everything else but clearly this mental picture conflicts with dependent origination.
Ultimately, Time exists only conceptually, i.e. as a mental formation. Thinking about past, present and future are mental events, happening in the present moment.
We live only for one thought-moment at a time (momentary death).
The mind might be chasing after some object or running away from another object but that also takes place in the present moment, thus we are always in the present moment.
Conventionally, we can speak of Time as existing and exercising some kind of control over beings in conditioned existence. That can be seen in the workings of Kamma. Kamma is fourfold and one of its classifications are called &quot;Time of Ripening&quot;1, i.e. when the kamma is coming into fruition.
There are actions that might produce their effects in this very life, they are called Immediately-Effective-Kamma.
There are actions that might produce their effect in a subsequent life, they are called Subsequently-Effective-Kamma.
Then there are actions that might produce their effects in any life as long as one is in the conditioned realm, they are called Indefinitely-Effective-Kamma.
As seen here Time exists conventionally, as do beings and rebirth, since they are merely concepts, conventions and designations. Ultimately though, these concepts are not findable or inherently existing. In other words they fall under the doctrine of Emptiness (Śūnyatā).
To further illustrate the difference between Conventional and Ultimate reality let's take a look at a quote from the Milindapañhā2 where King Melinda discuss Time with Ven. Nāgasena:

“Nàgasena, when you say, ‘Time immemorial’, what does time mean? Is there any such thing?”
“Time means past, present and future. There are some for whom time exists and some for whom it doesn’t. Where there are beings who will be reborn, for them time exists; where there are beings who will not be reborn, for them time does not exist.”
“Well put, Nàgasena, you are clever in reply.”

As we see here Nāgasena explains that Time exists for beings that will be reborn, i.e. beings that are still wandering in the realm of Samsara.
Time does not exist for beings that will not get reborn, i.e. those who have won Nibbana.

1 Comprehensive Manual of Abhidhamma, Ch. 5: &quot;Compendium of the Process-Freed&quot;, p. 201, by Ven. Bhikkhu Bodhi
2 The Debate of King Melinda, Ch. 2: &quot;Rebirth&quot;, p. 47, by Ven. Bhikkhu Pesala