My warm water heater is part of my heating system and keeps 60-100 liters of hot water available throughout the day. I now run it only between 6AM and 2PM. This has not affected our comfort level, as we have a full boiler at 2PM, but it avoids the system turning on every ~2 hours to top up the warm water.

Just this change has resulted in over 10% savings on the yearly electricity bill.