I change the oil in my 08 S60 at 7,500 miles. I’ve owned it since 31k miles and it now has 211k on it. I have done 3 UOA’s on it, with the last at 196k and Blackstone said the oil was perfect.
I have run Castrol Edge 5w30 and now run AMSOIL OE 5w30. The TBN on the Edge and the OE was about 2.0 at 7,500 miles, so it didn’t have a lot of life remaining.
So, if you are running a quality synthetic 7,500 is no problem.

 

I agree with 7500 being no problem with a quality synthetic, even with a turbo. I used Mobil1 exclusively at 7500 mile OCI when I owned a 93 MR2 Turbo. Did a couple UOAs and blackstone results were typical for the car's age and mileage, i.e., the OCI was fine.

My 2018 V60 T5 Dynamic OCI is apparently 12 months or 10,000 miles.