YZ250f dirt bike oil change?

Ok so i recently purchased a Yz250f '03 model. And in the guide book thing it says that the bike takes 1L oil normal change and 1.2L oil if you're changing the filter. I purchased 10-40W 4 stroke synthetic motorbike oil. Which changed into US dollars costs 10$ approx. My question is do i have to change oil every 5 hours?? I won't be racing on it or riding the throttle, mainly riding through my field/farm and not really jumping. Also with the oil filter, how often?YZ250f dirt bike oil change?Yeah, like Bob said, for an average trail rider that is changing the oil pretty much every ride which is not necessary. For a racer that's 5 races (5 weeks) and yes a racer should change their oil after 5 hours but these guys run a 250F practically wide open for those 5 hours. Once a month like Bob said sounds reasonable for trail riding. Always change the filter and if it has a little rubber O-ring like the CRF always have one on hand since they will break sometimes.YZ250f dirt bike oil change?I don't know where you got 5hrs from but that would mean you'd have to change your oil every day.I change mine once every month and don't have any problems in years of riding