The Do's and Don’ts of Buying the Perfect Christmas Tree

— -- intro:Nothing says Christmas more than trimming the tree. But sometimes the quest to find that tree can be a challenge.

When real Christmas trees can cost hundreds of dollars, the pressure is on to find the perfect one.

Veteran Christmas tree sellers Jamie Jones, Charles Poekel and Francois know their trees. Here are their secrets for buying and taking care of your Christmas tree this year.

quicklist:1title:Size makes a difference.text:The most common mistake that Jamie Jones said he's seen is people buying the wrong size tree.

"I would say it's when people pick out a tree that's just a little too big," Jones, who has sold thousands of trees at the Jones Family Farm in Shelton, Connecticut, told "20/20."

Before you take it home, make sure the tree you choose can fit inside the door. Jones suggests using a tape measure in your room to truly get an accurate size before you shop.

quicklist:2title:Buy your tree as soon as possible.text:Don't delay buying your Christmas tree, according to Francois, who only goes by his first name. He journeys from Quebec, Canada, and lives out of a van parked on Broadway while selling trees to New Yorkers every day until Christmas. He is profiled in a new documentary called, "Tree Man."

"If you wait too long ... all the best trees will be gone," Francois, who has sold trees for 10 years now, told "20/20." "I always tell people, 'Early buyers are happy buyers.'"

Francois said the best trees are the freshest trees, so the sooner you buy it after it's cut, the longer it will last in your home.

quicklist:3title:Pick a heavy tree.text:"A heavy tree is a healthy tree. It's as simple as that," Francois said.

When a tree is heavy, that means it’s full of water, Francois added. "Dry wood means a dead tree."

quicklist:4title:If you have a pet, take this tree home.text:To deter your pet from using your Christmas tree as a bathroom, pick a tree with sharp needles.

"The best tree for [pet owners] would be the Blue Spruce, because it has very sharp needles," Brooklyn tree seller Charles Poekel told "20/20." "So the cat, once they find out those needles are sharp, they want nothing to do with that tree anymore."

quicklist:5title:Keep enough water in the tree stand.text:Poekel, who, believe it or not, fell in love with selling trees after buying a stand simply to have a set to use in a movie he was making, has another secret he shares with his customers: He suggests spritzing the needles with water.

But all three tree men agree the most important secret for a healthy tree is having enough water in the stand.

"The first night people get home, I recommend they use warm water. It helps kind of defrost the tree and absorb better," Poekel said.

"Just tap water is all you need to use," said Jones.

They all warn customers that the most critical thing is to never let the water go below the bottom of the trunk. If you do, the tree will naturally form a seal, and then, no matter what you do, it won't absorb any more water.

Many people have heard that putting aspirin or soda in the water will make the tree live longer, but Poekel, Jones and Francois all agree that those things don't work.

quicklist:6title:For the best tree smell, choose one that “sweats.”text:That’s right. A tree used to frigid outdoor climate will naturally sweat when it comes indoors. The trees expel water from the interior, and that’s what gives off that great Christmas tree smell, according to Francois.

For example, Francois said the Balsam fir, which is native to Canada, is not only the most fragrant variety, but it will also sweat the most because it has been exposed to warm temperatures much less than say a North Carolina tree that has lived through warm summers.