Had one for years, good tool. One of the belts will wear quicker than the other so you might think of changing occasionally but no real need. Looks like yours has been modded with 2 strips of angle carrying the 2 front side wheels as usually there are 3 small metal roller type 'wheels' across the front edge but they tend to block up and dig-in. Mine is on a compact Kubota 3 speed pto which I usually use on mid-speed in second gear which probably amounts to 540. No doubt if spares were needed they would be usual 'gold-plated' prices. After some blades at present, just as spares, cheapest by far are in the USA but postage is over 3x their basic price.
Regards Phil