Incomming water temps play a factor in winter for warm rinses.......
but as useing FL's mainly as daily drivers, for the most part, warm/warm is always the preference, not so much as water expense, but heating the water is the concern.....
I conserve for myself as needed, not for the environment.......most all wash water is drained out onto the lawn, which is super plush deep green, on one side of the house only...lol.......
as for water useage or waste, I pay a flat rate per quarter for 26000 gallons($50.00), what I hate is during summer restrictions, It is requested to reduce water useage, but my bill does not go down for lower consumption, and I know what some of you guys are gonna say about running out, but we never have, so I never pay attention to it........as for possible waste, I have running water in a wash-bay of the garage(not attached to the house, and only heated during use), even during the winter, and although the pipes are wrapped underground, rather than pay the expense of digging up the ground to replace a frozen busted pipe, I let the water drip all season long.....have never gone over my limits, but if I did, its only 1.50 per 1000gals, cheaper than a plumber....