I've found 5k/6 month (whichever comes first) OCI is the sweet spot with most vehicles.
I personally prefer to only use Dexos 1 Gen 3 Full Synthetic High Mileage oil (to treat oil seals as well to prevent future oil leaks).
This interval and oil prevents sludge/varnish buildup.
Some things which convinced me this this is the right interval:
A few videos on youtube about "Million mile Joe", who owned an early 1990's Honda Accord since new and took it to 1,000,000 miles doing oil changes about every 5,400 miles.
Also there is another video about a husband/wife traveling performers in the south who took a 1990's era Honda Civic hatchback to 500,000 miles doing oil changes every 5,000 miles.
I personally prefer to only use Dexos 1 Gen 3 Full Synthetic High Mileage oil (to treat oil seals as well to prevent future oil leaks).
This interval and oil prevents sludge/varnish buildup.
Some things which convinced me this this is the right interval:
A few videos on youtube about "Million mile Joe", who owned an early 1990's Honda Accord since new and took it to 1,000,000 miles doing oil changes about every 5,400 miles.
Also there is another video about a husband/wife traveling performers in the south who took a 1990's era Honda Civic hatchback to 500,000 miles doing oil changes every 5,000 miles.