Grease Kingpins of course every 1000 miles though I do mine every 500. An easy DIY job.
I changed my Auxiliary Belt at 7 years for peace of mind though the original looked fine. The Original Gates belts are about £11.00 and take 5 minutes to fit.
Check exhaust rubber bobbins and rear rubber mounts. Easy DIY job and You can buy the 4 bobbins and rear mount for around £15.00
Air Filter change on mileage/condition. I have a K&N in the factory housing. About £36.00 for life.
Tyres I changed all mine at 8 years though they had only done 13,000 miles and werent half worn. Full set of 4 Vredesteins around £200.00 fitted