Under Roman Republic one unskilled worker typically made one sestertius a day, and it was enough to keep up a modest life in ancient Rome back in the day. But I found data about Rome started to decrease the silver content of the coins denarii and sestertius, so they could mint it out of more common metals like bronze. So the value decreased significally.
Here is a quote
Like coinage of today, Ancient Rome's coins represented portions of larger denominations. The As, the basic unit, functioned like our penny. And like our penny, through inflation it experienced a loss of buying power. During the time of the Roman Republic, you could buy a loaf of bread for ½ As or a liter of wine for one As. A year's pay for a commander in the Roman army around 133 B.C. was 10-2/3 Asses, by Augustus' rule (27 B.C.-A.D. 14) 74 Denarii, and by the reign of Septimus Severus (A.D. 193-211), it rose to 1,500 Denarii.
So until Augustus the coin was relatively valuable, but in like 200 years it's value decreased significantly, which means roughly 2000% devaluation altogether.
As the chart shows, the Denarius finally lost most of it's value between 200-320 AD.
Note: the two sources are a little bit contradicting in dates, however whichever is true, the question still valid.
I listened a podcast from Stefan Molyneux (historian-philosopher) who blamed the debasing of currency as a main factor in fall of Rome. Is it accurate statement? Was it a symptom or cause?