If u r using any simple miniral oil like shell yellow, red... castrol gtx n etc... soo i suguest u to change it on max 4000 km.... if u r using any simi syenthic oil like.. caltex havoline formula... zic hiflo... shell blue... soo it must be change on max 6000 km.... & if u r using fully synthic oil like ZIC A+ or Caltex Magnetic (Both are best oil in all) soo for these i suggest u 6000 - 10000 kms..... depands on driving conditions...
and 1 more thing if u r filling up ur engine with fully synthic oil so pls must clean ur engine with taking 4 litre any oil which is cheapest like shell red.. or any local golden... total...etc... company oil of 20-50w.. thn mix 2 litre diesel in it completely... and take any local cheapest 2 oil filters...cost for both is rs. 200 max...
thn fit the the new oil filter and fill the mixtute 2 litre in engine... thn run ur engine approx 1 minute at max 2500 rpm... thn pull out the mixture oil from the bottom... thn again do tht same 2 more times by remaining mixture of oil and diesel... bcoz u made 6 litre mixture.. use 2 litre on each engine flash... and pls must not go over 2500 rpm... and 2 min...
after done it 3 times... ur engine will completly clean inside... thn use ur desire oil... but i only suggest ZIC A+ & CALTEX MAGNETIC...
aND If u have much money soo i recommand u ZiC XQ.... This is only and fully synthic premium engine oil... but its too costly like 2500 rupees.. whn ever zic A+ Is for Rs.1650 and Caltex magnetic is for Rs.1850.....
but u can easily run ur car between 10000 - 15000 km on ZIC XQ...
But remember 1 thing tht all its depends on ur driving conditions...