It's no problem leaving HSS as default.Your flash works much harder during HSS, and produces less light while doing so.
So there are at least two problems: 1) the increased power consumption will wear down your batteries faster, and 2) the increased power consumption will heat up your flashes faster.
They would only be an issue if you were constantly shooting above sync speed. Even when HSS is selected it doesn't actually come into effect until you do go over that magic figure, so keeping your flash in HSS just means you don't need to push another button when you get there.
There is nothing wrong and you will cause no additional wear, heat or any other issues if you keep your flash in HSS.