The first question to ask yourself is whether your price, the listing or your house is to blame. Are you getting tours but no bids, or are potential buyers simply staying away entirely?
If it's the first, people are intrigued by the house at the listed price, but are put off by something they see in the tour. Is it something you can fix? If so, you might be able to keep your asking price with some aggressive fix-up, cleaning, remodeling or home staging. If fixing the problem costs less than a price reduction, you might consider (quickly) doing the work. If you can't or don't want to fix it, you probably need to lower the price of the home.
But what if the phone is silent? In that case, it's a good bet your listing or the price is to blame. To figure out which it is, ask your real estate agent for an updated competitive market analysis (CMA). The CMA shows how your house stacks up to comparable properties. Take a clear-eyed look. If your house is, in fact, already priced in the lower end of the quiver of comparables, you might ask what your agent is doing to create interest. How's the online listing? Is it well written and illustrated with pictures that put your house's best face forward? If not, revise and repost it, or get a new agent.
But if your listing is fine and you're past the average DOM without interest, it's time to cut the price. By how much is another story, with the absolute minimum being $5,000 and the maximum being the amount that takes you to lowest price in the list of comparables.
Other reasons to reduce your asking price include an impending deadline (if you gotta move, you gotta move), or an obvious error in initial pricing, perhaps due to a quickly declining market, your unfounded optimism or an agent who quoted a too-high asking price in hopes of buying your listing.