15W Fork Oil. Does it make that much difference?

[kebab19]

Japanese springs usually last a long time, I would estimate they'd only change a couple of mm in 50000 miles or possibly the entire lifetime of the vehicle

I think changing fork oil should be done reasonably often, i go for every 2 years or 10000 miles, whatever comes sooner. I realise others never change theirs as its 'non-scheduled maintenance' according to Mr Haynes