If i service my bike every year change all filters, spark plugs ect will that affect the resale of the bike if i ever sell? even if the work that i do is not different to a garage and i keep all proof of purchasing items ect?
For your own purpose of knowing what you've done to the bike a record is best kept and costs recorded, so then you know your costs and if you come to sell it, the records are there for the punter to see.
Been doing this for the last 50 years on all the bikes I've had.
a brand new bike should be serviced at the franchise dealer for the first couple of years, they will fix any known problems, sometimes without the owner being aware of it. After that DIY is OK, although it depends on the bike.
some bikes are sold with a FSH Full Service History but my Yamaha XT600 had no service history at all and it is fine. You will probably save more money on service costs than you will reduce the value on resale.