Been wanting to add a postscript to this thread about oil changes & regular short driving distances.
Lately, due to lockdowns in "the greatest lockdown city in the world - Melbourne" & due to a lack of work, I haven't done my usual 30-45min driving trip every morning/arvo's 5 days a week but far less & more of the short 10min stints.
My latest 7,500kms was a mix, mostly longer fwy distances but also a lot more of the short & the car was due for a service which I did a week ago. I replaced the oil with Nulon Full Synthetic 5W30 & replaced the oil filter as I usually do & was very surprised to note a tiny amount of sludge/dirt in about 3-4 spots on the filter inner creases.
Engine air filter had also become a little dusty for it's 20K kms but was still fine for another 7.5K km stint.
Goes to prove that even at 7.5K kms on a relatively new car with oil that looked perfect in colour & consistency, short trip type driving is quietly at work in the background wreaking havoc on your engine. I definitely wouldn't go beyond the 7,500 kms OCI if you only typically do short driving stints.