I use Zic 10w40 Fully synthetic (X7) with original "VIC" branded filter and "Guard" brand Air Filter. I change all oil, and both filters exactly at mileage of 8,000 Kilometers.
When i do not get "Vic" oil filter, then i use "Guard" filter and then i used to change oil & both filters at 6,500 Kilometers.
When i had carby cultus, i used zic 10w40 (X7000) which was also fully synthetic, mileage interval i always follow sam (if using good Quality oil filter)
8,000 Km for Fully synthetic
7,000 Km for Semi-Synthetic
6,500 Km for Synthetic Formula
5,000 Km for Mineral oil