How are you controlling the relays? Unless you have an extremely small reed relay there has to be something between the relay and the MCU's GPIO pin, as those pins can't drive the relay coil's current requirement on their own.
As long as whatever's sitting between the MCU and the relay doesn't require more than 10 mA, and the sum of current supplied by all pins is under 100 mA, then there's no problem leaving it on 24x7.