The featured should be always kept dry for proper functioning of the machine. Since it is electronically connected, spraying of water and other greasy elements or soapy water results in the damage of the timer. Hence after the washing process, it should be kept clean and dry. Installation of a new one can be made with the help of an experienced service person. It helps in setting certain cycles in the movement of the washing machine and the knobs should be used with proper care.
You can also buy washing machine parts from a bricks and mortar store - if you can find one nearby. You will often have to end up ordering it at the store and then going back to collect it when it finally arrives, as many stores do not keep any but the most common parts now. They do this to reduce their own costs as it is no point them carrying a lot of parts that may well not be needed. They could sit on the shelf for years until that model appliance went out of date and then they would never get sold.