It's an important question. Does your larger lawn need a compact ride-on mower or a large scale tractor?
We have covered cutting widths and sizes of lawn in another article see what size cutting width do I need? so let's just have a look at a couple of the other factors involved.
You don't need a huge estate to be thinking about a ride-on mower. Many compact rear engine riders are more than ideal for gardens of around half an acre and will easily fit through a standard garden gate.
Half an acre is around 2023.429 M2 or, very roughly, around a quarter of a 'standard' association football pitch. (See image below). This is very approximate as football pitches can vary widely in size)
Rear engine riders will generally have a single blade deck (see image below) and cutting widths varying from around 66cm up to 77cm or so. They are specifically designed as mowers but some are able to tow lighter attachments such as trailers.
Rear engine rider singe blade cutting deck
If your garden is around the two acre mark (so that's around the size of a whole football pitch - see above) The you will probably need something a little larger, like a lawn or garden tractor.
These will be powered by one or two cylinder engines, often have hydrostatic drives for infinite speed control or multi-gear systems. They will have wider cutting widths and are designed for more multi-purpose use than rear engine riders, able to tow heavier attachments. They will tend to have decks with two contra-rotating blades for a wider cut. (see image below)
Lawn and garden tractor double-blade deck
Obviously, the larger your lawn and garden, the larger tractor or mower you may want, and factors like inclines and awkward terrain may also affect your decision. Large zero turn and out front deck machines are also ideal for large lawns and gardens of 2 acres plus.