What does your agent say, and why? Like others said below, your agent should have prepared a comparable market analysis for you and, I am sure, by looking for homes up till now, you have a pretty good idea of what is out there, for what price and the condition of the homes.
Days on Market does not necessary translate to an automatic % reduction on making an offer. How long has the house been offered for that price? Are there improvements made? What's the 'current' market condition - we are seeing a surge in Novato, Marin market at certain price range just recently. What's the motivation of the seller?
A good agent who understands the 'CURRENT" market and LOCAL situatioin with great negotiation skills will be able to get your the best deal. What does your agent say?