Regular cool water washing will cause a build up of unactivated detergent around the outside of the drum. This can cause smells and discolouration of the seal, and if left alone, could cause the bowl support to corode.
To prevent this, use a cycle of 60°C once a week, and every month or two run a cycle at the maximum temperature the machine can handle - normally 90 - 95°C. Limit use of very short cycles as these are generally not designed for 'everyday' use.
Top load washers are not as sensitive to cold water washing as front loaders, but an annual cleanout with Tricleanium™ will prolong the life of the internal metal components. The best way to do this is to fill the machine with hot water, add a couple f tablespoons of Tricleanium™, wash for a few minutes to disolve, then pause the machine and let it soak for an hour, then let the machine complete the cycle.