Lots of people refer to changes in technology Paradigm shifts, but the Roomba is the only one that I have ever found to meet the definition.
Vacuuming was once seen as the Homemakers job, a role traditionally filled by the lady of the house. But the Roomba has changed this to a mechanical job, like maintaining the car or other mechanical systems. I am no longer vacuuming, I am servicing the robot, thank you very much.
Seriously though, as stated earlier, they do a great job of ‘floor dusting’… corners are notoriously difficult, and they need to be emptied very frequently. But, they can also be run frequently, without you having to do much more than start it (if you don’t have a model with a scheduler built in), and rescue it when it becomes trapped. They are really good a keeping stuff from accumulating under the couch / bed. But it is no replacement for a good, focused multi-tool vacuuming.
As far as maintaining the Roomba itself, they are well designed, and most functions are ‘compartmentalized’ and can be replaced by someone with medium level mechanical ability. The only thing I have not been able to fix on my Roomba is one of the main Drive wheel assemblies - if that breaks, the whole assembly needs to be replaced (I had one that did not turn well, and figured there was something wrapped around the axle and jamming it. There was no way I could find the remove the wheel to clean it out.) But Brushes / Batteries / Filters - easily replaced with parts found conveniently online. Heck, you can even get After Market Vacuum units to swap in if you find it not up to your needs.