I doubt that, of itself, is a problem - my garden is big enough to need several Robot Mowers
... I used to do it with a ride on (model had 60" cut and was chosen to make the job quick, so although area was large and has complicated shapes / paths etc. it only took me 1h30m). Mower was knackered, noisy and a brand new top-of-range model which would have done the job in the same time was expensive ... and worked out same as multiple Robot Mowers. Now I save the 1h30m a week, don't have to fret if we have weekend guests coming and it is raining on a Friday "Mower evening" ... and every morning when I get up the grass looks freshly cut 'coz it is. Heavy land here, always used to be a problem to try to mow in winter and spring when it was sodden - the Robots are light and have no problem with that.
Its not without problems e.g. if the perimeter wire gets broken (finding where the break is) [
newer models use augmented GPS I believe, so no perimeter wire], but other than that hassle free, negligible maintenance (razor blade type things replaced a couple of times a year for a few £quid), no hassle with getting fuel or the blinking pull-cord snapping and then spending an unscheduled hour fixing / fighting with the mower, and I'm not part of the mower-weekend-noise-pollution problem in the neighbourhood! ... well, "works for me" I guess
Definitely only worthwhile/affordable, in my case, 'coz my mower was knackered and needed replacing anyway.
lack of power in the storage sheds
Definitely a snag! I put power to mine 'coz lack of power was a hassle - I wanted CCTV (put a cable in for that too to avoid trying to get WiFi longer distance, and put water pipe in the trench too ...) and ability to charge garden stuff (got an electric mini-quad bike for towing garden trailer etc. That was a good purchase too, £2K ... but sadly lead-acid
, Way better than the ICE tug/ride-on that I had before). But unless you could garage the Robot next to house, and it could "drive" to lawn from there, then yup! it (
i.e. each/all of them ...) would need power at its garage.