i meant problem, which i never had, the 1st marker i had i never understood and never really cleaned it properly, and it caused me headaches, until i realised that good maintenance took the issues away, why would anyone need to have a marker serviced if you regularly look after it yourself... I have not looked at the newer markers, but certainly would of thought the same applies, unless you have a failure or physical break of something, then there should be nothing going wrong if cleaned oiled and maintained properly...