>>3766490>you need to check shutter counts. they have a finite amount of counts before it breaks
The shutter count gives you an idea of how long the camera has been used.>mirrorless you don't have to worry about this
It's still worth knowing because sensors get hot pixels and dead pixels over time. And they also have shutters. The difference is that there's no mirror mechanism, but for example Sony curtain shutters are known to fail.
Shutter count is a parameter you want to be as low as possible.