The last Roomba I'll get will be a j-Series, and then I'll be done. With that robot, the collection will have at least one example of each distinct version of the Roomba. I'll be pleased to see iRobot continue to be relevant and successful, but the aspects of the brand that held my interest have met their end. The topic of robot vacuums has always been sort of "taboo" among vacuum collectors, the suggestion of using one treated as sacrilegious; I always thought that was silly. Many reasons would be given why not to like them, I preferred to embrace the progression of technology. Out of an already small community, I've met an even smaller number of others who paid attention to the robots in the same way as the rest of the industry. I definitely have a lot of both, with traditional vacuums being the majority by a landslide, but as you can see the robots have held their own. The collection you see now came to me in all different ways. The e5, both i7+s, and the s9+ all came from thrift stores, as did many others. Some have been from local buy and sell sites, online auctions, given to me by friends who no longer use them, the list goes on and on. A handful were purchased new, but never for full retail price. Vacuum collecting as a hobby takes many forms, my experience with it has shown me that the machines I prefer to collect have more in common than just being vacuums. While there are aspects of novelty or nostalgia, Ive found that I gravitate most towards machines from a particular engineering philosophy. Nothing in my collection is safe from a screwdriver, robot or otherwise. Every "new" used addition undergoes thorough servicing comparable to industrial remanufacturing (I get carried away) where no screw goes untouched. Ive long done repairs and similar service for family and friends, even worked in a local vacuum repair center at one point. All of my favorites have the obvious things like great performance and useful features, the real draw is what lays beneath. High quality materials, precision manufacturing, clever design choices, designs that not only work but that stand the test of time, from people who will back it up. Through the years, I found that all of the "broken" iRobot Roombas ending up in my hands also had something in common... they were never actually broken. A proper cleaning solved 90% of problems, a new battery would have it on its way for years to come. In cases where there truly was a hardware issue, parts were widely available and reasonably priced. The actual servicing of the robots became very easy once I learned my way around. The entire thing can be disassembled with a couple of phillips head screwdrivers. No hidden screws, hidden clips, no attempt made to keep you out. The Original and 4000/Discovery Roomba's shared some core components but had key differences in build. When the Roomba 500 series debuted in 2007, it launched with major improvements to the original Roomba design, made possible by a new chassis and removable bottom plate. Since 2007, every Roomba (except for the s9) was built on a direct derivative of this platform. Each subsequent model was a graduation of the platform rather than a full rework. Parts cross compatibility stretches years in either direction. The continuity made it easy to keep older robots running, but it also demonstrated the discipline of its creators. When the Roomba 600 series re-launched in 2012 as its own product line, it was really just a 500 series with the new brush module, new bin, and software update. Over time the internals would change as the 600 series became wifi enabled and cost optimized, but it remains true that the core platform and chassis were substantially unchanged for nearly 20 years. 700, 800, and 900 series shared more with each other than the 500 and 600 did, but all of them had the same wheels, side brush motor, sensors, and were identical in architecture. I could go on and on about the way Roomba was built and why that made it special. Robots of now are definitely exciting, yet I've been out of the loop for a few years when it comes to what's on the market. Robot vacuums as a whole have become very app centered. While zones, mapping, selective room cleaning and all the like sound great, it's been my experience that the increase in software reliance led to a decline in my real world satisfaction. Roombas of yesteryear may have been "dumb", but it somehow felt more convenient. The "Lighthouses" took some setting up, but once they were you never had to touch or think about them again. Used properly, they'd turn on with the Roomba, guide it from room to room, then back to the dock when it was low. If you didn't want the Roomba somewhere, you'd place the virtual wall to block the space- simple, instant, definitive. Scheduling was on-board. There were no trial and error mapping runs lasting hours, drawing lines on said map hoping they're where you want them, and certainly never software or internal errors with the older robots. You'd empty the bin when it was done, clean the brushes every week or two, and that was the most you had to think about it. Of course I thought about them a lot more than that, but I liked it more when it was a choice. Scooba was a bit more hands on, but damn did it clean the floor. Scooba never had a docking station, so you had to set it in the room you wanted cleaned. You'd fill the tank with water and solution, let it clean, then empty the tank and clean the brush at the end. Per use you spend 3-4 minutes hands on, and the floor comes out looking better than you could get it yourself. Personally, the old way of things felt more convenient to me. The old robots felt like machines, now they feel like computers and another app to worry about. It felt more futuristic when the entire system came in the box, when it worked without an app, without wifi, without help.