"The Romans recorded most of their day-to-day transactions by incising the wax covering of wooden oblongs about the size of modern roof shingles. This medium was highly perishable, and we have almost no written records of such transactions after two millennia. We therefore are dependent on four kinds of evidence: casual remarks ... in works of literature that have been preserved for other reasons; proclamations or directives important enough to be chiseled into stone; archaeological evidence; and papyri from Egypt...."
"The Economy of the Early Roman Empire," by Peter Temin; The Journal of Economic Perspectives, Vol. 20, No. 1 (Winter, 2006), pp. 133-151.
It's fascinating to learn about how ancient people lived, but most of what we "know" we only guess at. Archaeology provides us with most of our material facts about daily life and analysis of literature, especially satire, and other writing (like inscriptions) allows us to guess at other facts, but
- New research will challenge/overturn many current theories.
- Standards of scholarship were not the same as current ones. For instance, Aristotle is used as a source on ancient tragedy, but he didn't have all the material that we could think of as the necessary data to justify making the statements he made.
- Manuscripts have been lost and destroyed.
- Most of the materials -- like cloth -- of daily life have long since disintegrated.
- One of the best sources for official history, coins, don't celebrate the mundane events of daily life.
- The mundane details of daily life were considered simply too ... well, too mundane to record.
- Ancient history spans millennia. What was true one century and in one place may not have been true elsewhere or at another date, so what we know of Hellenistic Greece is not necessarily relevant for Republican Rome or Archaic Greece.
- We know something about food from such odd sources as medical writing and tombs, but we don't know how representative these "recipes" were of ordinary meals.
- We know more about the exceptional because those are the people / deeds / events that caused enough interest to be recorded.
- Writers have their own agendas.
The list of limitations goes on and on. Consider this a caveat for the entire site:
Most stated "facts" about ancient history should be considered interpretation or theory.