Replacing Spark Plugs

How many kilometer do we need to replace the spark plugs?
My car is a 2014 4-matic and I have only 40,000 km on the vehicle.
Is it an easy DIY? I watched the youtube video and it seemed pretty easy.
Last edited by 77Tony; May 4, 2020 at 12:15 PM.

However, I am still interested any members have done the spark plugs replacement before?










