thank you very much for the info but can you enlighten me about changing oil which has passed its date? for example for semi synthetic after 5k km we know automatically its time to change the oil but what if its just a weekend car for example just reach 2k++km but the date has passed (usually 3-4 month) can we continue using the oil or change it? wht bout the filter continue to use it or replace?? thanks in advance
That's actually a good question. I don't have any scientific proof but I believe oil left alone eventually will be exposed to moisture and humidity fluctuations (rain, extreme heat) etc. Anything exposed to moisture can't be a good thing. So what I normally practise is I don't leave mineral oil longer than 4~5 months, semi's no more than 8 months and fully syns no more than a year. I'd change it even if it hasn't reached the mileage OCI. It might be overkill but better safe than sorry.
The oil filter is there to filter debris, sludge and whatever the oil managed to remove or leave behind. If the car rarely moves and hasn't reached the OCI, I wouldn't worry about it until you're ready to change the oil.