During a routine oil change on May 16, 2023 the mechanic recommended replacing both rear shock absorbers because the left one is weeping oil. I declined.

However, I remember seeing that the left rear shock absorber is dirty when I first got the car but I was ignorant of the cause back then. Dirt adheres to the oil that's coating the shock absorber shaft, that's why. After I wiped it clean, I reinspected it weeks later and got a bit of oil in my hand so it's confirmed. I also touched the shaft of the right rear shock absorber and my hand doesn't get as dirty and oily. I researched online and weeping oil is not a serious problem with the shock absorber so I decided to forgo replacing the rear pair right now