When's the best time to sell or buy a used car? It may be different than you remember.

Instead of planning your Labor Day picnic, you might want to spend some time preparing to sell your car to ensure you get top dollar, according to CarGurus. 

Traditionally, April has been the best time to sell your car but like everything else in the car market, the pandemic has changed that too, the car buying and selling platform said. Now, the best time to sell or trade in a car is just after Labor Day, which is Monday, CarGurus said.

The firm examined used car prices and inventories over the past seven years to account for pre- and post-COVID trends. However, it excluded 2021, given the outlier of a year it was in the automotive industry, it said. 

"Consumers looking to get top dollar will need to hit the accelerator," said Kevin Roberts, CarGurus director of industry insights & analytics, especially because "we've begun to see average listing prices for used vehicles start to decline, with further declines expected this calendar year."

In the three months ending in June, used vehicles cost an average $29,472, down 4.6% from last year’s record $30,905 but still a steep 46% increase from 2018’s $20,153, Cox Automotive said.

How much more can I get if I sell just after Labor Day? 

Data shows that used car listing prices are 3.2% higher, or approximately $1,000 more just after Labor Day, compared to the average week. Part of the reason is because the average number of available listings were 6% lower during that 36th week of the year, CarGurus said. 

What do I need to sell or trade in my car? 

States differ on what’s needed to sell or trade in a car so it’s best to check with the department of motor vehicles near you. However, here’s a list of what paperwork you’ll need in most cases: 

• Car title: a legal document showing proof of vehicle ownership that's required to transfer ownership. It contains information including vehicle make and model, its identification number (VIN), and year of manufacture, owner's name and address, and any debt associated with the vehicle. If you still owe money on the car, your lender has the title in 41 states. In Kentucky, Maryland, Michigan, Minnesota, Missouri, Montana, New York, Oklahoma, Wisconsin, the registered owner of the vehicle holds the title. 
• Odometer reading: this document shows how many miles the car’s been driven. 
• Maintenance records: shows the car’s been well cared for to get top dollar. 
• Vehicle history: using the VIN, you can obtain a report through a company like CarFax or AutoCheck to show if the car’s ever been in any accidents and how many owners it’s had. 
• Warranty: if the car still has a warranty, it will boost your car’s value. 
• Emissions report: some states like California require cars to pass strict emissions tests prior to being sold. 
• Bill of sale: a document stating all terms of the sale, including date of sale, a description of the vehicle (including its make/model/year and mileage), the sale price for the vehicle, and the full names and addresses of both the buyer and seller. 

Is there a best time to buy a used car? 

Just as the best time to sell a car has shifted, so has the best time to buy a used car.  

Instead of the early January time frame we’re used to when dealers try to sell off their inventory to bring in newer models, the best time to shop is now mid-February, in line with traditional Presidents’ Day deals each year, CarGurus said. 

How much can I save on a used car? 

CarGurus data shows used prices around Presidents’ Day could save you 2.8%, or about $900, compared to the average week. 

Listings for used cars nationally were about 6% higher than normal near the holiday, the third day Monday in February, which not only pressures prices but offers buyers a slightly larger selection.

Medora Lee is a money, markets, and personal finance reporter at USA TODAY. You can reach her atmjlee@usatoday.com and subscribe to our free Daily Money newsletter for personal finance tips and business news every Monday.