Conserving water is primary now adays. What I do to conserve water when I need to wait for it to warm up for doing dishes or for the bath or shower... I turn the faucet on so that only a trickle of water exits the faucet. Hot water still ends up coming out of the faucet but NOT in a rush. Thus I'm conserving on the number of gallons of wasted water exiting my faucet. When ever possible I use that trickle of water by filling clean plastic bottles to water my plants or add to the bird bath outside.
If I hand wash dishes I'll wash several, leaving the faucet off until I wish to rinse that batch of soapy dishes. Then I proceed to several other batches of dishes and rinse them in the same fashion.
Water is one of our most precious resources and we should do everything we can to conserve it.