Business Insider recently conducted a survey of real estate agents across America to gain insight into their jobs, what clients should know, and what makes a home “unsellable.” Many believed that any item could be sold at the right price. Some believed that location, death in the home, and unpleasant odors from cats were some of the things which could make selling a house nearly impossible.

Here are 11 reasons why your home may not be marketable, according to real estate agents.

1. Undesirable locations such as being close to an airport or frat home could present challenges.

Butch Haze, who has sold homes ranging in value from $3 million to $10,000 within The San Francisco area, told Business Insider that location is key. In San Francisco I will also be alert for power lines that block views from windows. Space may be scarce here but backyards still matter,” he noted. “Location matters.”

Elana Delafraz from REAL New York states that homes near fraternity homes or airports may be hard to rent or sell due to their close proximity. She typically leases out these houses within the city for between $3200 and $5,000 per month.

“Location is the biggest hurdle,” Gerard Marino, who oversees sales for a $300,000 to $500,000 region in southwest Florida told Business Insider. “A poor location can be remedied with lower costs.”

2. Overly optimistic price tags are often the cause of unrealistic price tags.

Some agents have noted that if homes aren’t selling, it could be because the cost is simply too high to justify.

Noemi Bittenman of Warburg Realty, who handles sales within New York City for homes between $500,000 and $1.75 million, explained that an “unsellable property” is one that’s not priced correctly.

3. Bad odors could deter potential buyers from visiting your house.

Many agents have pointed to bad smells as the top reason why homes don’t sell. Three agents specifically stated that cats’ fur can be particularly unpleasant to deal with.

Jose Laya, who sells houses in Miami for between $800,000 and $2 million, notes that smokey odors from cigarettes can be problematic.

4. Lack of natural lighting can deter potential buyers.

According to Michael Bello of REAL New York, who specializes in $5,000-a month rental properties for New York City, lack of light can make a home less appealing.

Lisa Camillieri of Warburg, who has sold homes within Manhattan and Brooklyn between $400,000-$1.2 million, noted that while any home may be marketable at the right price, lack of lighting can be one factor that “really turns buyers away”.

Colin Turek of Compass in New York City, who sells properties between $800,000 and $2 million, noted that no one would want to live in a cave. When remodeling your home, keep this in mind.

5. Death of a family member can make it difficult to sell the home.

Delafraz from REAL New York noted that the death of a homeowner could make the sale process more challenging.

6. An inefficient design that isn’t altered can quickly make a home unsellable.

Robin Kencel of The Robin Kencel Group at Compass in Connecticut, who sells homes ranging in value from $500,000 to $28 million, explained to Business Insider that homes that are unmarketable “are those that cannot be altered due to geographic issues, low ceilings, complex floor plans that cannot be altered easily and poor design,” explained her clients about properties with marketability issues.

7. Environmental issues such as mold or other types of mold are serious matters, according to Kencel. “Mold in wall surfaces” could make a home unsellable, he noted.

Sometimes, even serious problems may go undetected at first.

“What lies beneath the hood?” asked Gill Chowdhury of Warburg Realty, who offers homes for up to $2.5 million in Manhattan.

8. Concerns with structural or maintenance could potentially force a home onto the market.

According to real estate agents such as Rob McCann of Pennsylvania who typically sells homes around $210,000 on average and Jason Tsalkas of Compass who specializes in homes between $650,000-$2 million with most sales taking place in Brooklyn, failing to complete necessary repairs and renovations can make a property unsellable.

9. Dingy or poorly decorated décor could be a deterrent.

According to several real estate agents interviewed by Business Insider, properties with discolorations or poor aesthetics tend to take longer to sell than their more up-to-date counterparts.

Eric Mendelsohn, who specializes in selling houses for an average of 1 million dollars in New York City, advises against selling a house that appears to be out-of-date.

Eric Goldie of Compass, who handles sales in New York City for an average of $1 million to $5 million, noted “terrible interiors and old kitchens and bathrooms” as potential deterrents to purchasing a property.

Scot Dalbery of REAL New York, who manages rentals within New York City at around $4,000 per month, noted that while every property can be sold at the right price, small details like ugly kitchen counters may cause it to sell below its average market value.

“Fitting the tiniest details of your home, even if it means investing in certain upgrades,” according to experts, can increase the value of your residence.

10. Unorganized and poorly staged homes will be much less appealing to potential buyers.

Sellers must ensure their property looks its best in order to make it sell according to the opinions of agents surveyed.

Jared Barnett of Compass, who has sold homes ranging in value from $2 million to over $10 million throughout New York City, stressed the importance of performing all necessary cosmetic work as well as decluttering and staging prior to listing the property. “It is absolutely essential to do these steps,” he said.

11. Unwilling sellers could prove a deal breaker as well.

Maggie Ross of Compass Realty in Brooklyn specializes in selling homes between $2 million-$3 million. She noted that in some cases, it may be the owner of the home who can block its sale.

“Unruly pets or an unwillingness to work hard can be deterring from selling your house,” according to her. “Clutter, clearing away before showings, removing pets (especially smelly or loud ones) and having an attitude that doesn’t put yourself in the best light are all issues that could hinder sales.”