There would be nothing worse about remodeling or building a brand new home and then realizing that you did not leave enough space for installing corner hot tubs.  The walls must be left open and unobstructed in order that the unit can be brought in without a great deal of difficulty.  The floor will have to be reinforced because of the weight of the water when the tub is full.  That is something to think about as there may need to be joists placed in the flooring that will provide extra strength for the unit.  These things should be considered before purchasing.