Im currently using Planet 5W40 fully synthetic. Cost me like £15 for 5 litres but thats trade price, reccommended retail is about £20-£25. Its bottled by Comma, has all the approvals of top brands and aimed for trade use as garages can then charge £60 for a oil change making a tidy profit on consumables
I change mine every 6 months and even thats a bit of an overkill imo but its such an easy job (with my relocation kit) and cheap when im buying such discounted oil theres no reason for me to skip it.
I do find it amusing when i see people pay out for super expensive branded oil to then change it every 6 months or less! Yet these are some of the same people that are too tight to pay for a proper geometry alignment or get their car properly mapped, just seems odd to me :wack: