I would prefer half sizes.  I take an 8 1/2 or 9 and had to buy the combined 9, 9 1/2.  It is a little long and too wide.  I have to overlap the felt pads underneath the straps which cause sore, red grooves on my feet.  If I loosen the straps my feet flop a bit in the sandal. Also, the velcro straps overhang too much. The smaller size had to fit sizes 8 and 8 1/2 consequently my foot went from end to end with my heel resting on the rim which could cause callouses. The width was fine.  Probably a straight 8 1/2 or 9 would have fit me properly.