There are many reasons why somebody would buy second hand auto parts online. One is to get the best price. The other is to get the right part that they need and not have to go through the headache of going to different stores in person.
Secondly, buying used auto parts online is a great way for people to find parts for older cars that no longer have production and part availability. There are many sites that sell old car parts, so there will always be an option for people who have older vehicles or who just want a different one from time to time without having to switch out their entire engine system.
Thirdly, a lot of people like buying old auto parts because it’s an environmentally-friendly way to find automotive components as well as recycle what would otherwise be trashed in landfills.