Many Kenyans in the tour travel industry are not paid significantly well and therefore rely on tips. Therefore a tourist should tip the Kenyan staff according to the service they get. As a tourist you should tip according to what you know is well-deserved and you should do it in Kenyan shillings.
It is usually hard for Kenyans to change foreign currency since a significant amount is lost to commissions. It is also very fundamental to note that foreign coins cannot be changed.
These are some quick tips concerning money for tourists visiting Kenya