When buying a sit-on lawn mower it is important to consider not only the size of the cutting deck, but also the size of the machine.
For a truly versatile lawn mower you need to be able to maneuver around tight objects and pass through a variety of passageways and pathways, and to do this your sit-on lawn mower must fit through these too. The alternative is that you have to go back afterwards with a grass trimmer adding more time to the job in hand.