I said 81-95 back in Machina's poll (thank you for the reminder), and went for the 110-120 spot in this poll. I'm not sure how many system sellers Nintendo still has planned for the Switch, and I tend to predict conservatively anyway. As for the second question, just one and I don't plan on getting another unless Nintendo announces a 'Switch Pro'.

118 exactly. I can’t see the system having the super soft fall that many people think. I own two systems so far

2017 - 14.86m / 14.86m
2018 - 17.42m / 32.28m
2019 - 20.20m / 52.48m
2020 - 21.50m / 73.98m
2021 - 19.00m / 92.98m
2022 - 16.00m / 108.98m
2023 - 9.50m / 118.48m <---- Switch 2 November 2023
2024 - 5.50m / 123.98m
2025 - 2.50m / 126.48m
Lifetime - a bit under 130 million

Going by 120-130 million then. If Switch 2 is 2024 then 130-140 million.

Bonus; Only one, i see no reason to buy another one.

110 million. I'd love for it to do way more though.

There are 2 units in my home. One for me and one for the wife! My kids are too young for their own this time around, but I can see us getting more of its successor, but thats way down the road. 

Holy fuck. So much people said below 96million. 

Less than WiiU

..

..

(x12).

130m - best selling system ever

BQ - One system for now but with 4 joycons and 2 docks so only a tablet away from 2 systems. We'll have 3-4 eventually. 

I think 120 million is a pretty safe bet at this point.

I can see the Switch doing more, but I don't fully trust Nintendo yet. Latest case in point: Clubhouse games only lets you play with two players in most games, even games that require more than two people to play (the missing people are replaced with CPUs lol). Even Bowling can't be played with four people, and literally the only reasons I can think of for this is either laziness or the fear that customers are loudly going to demand another Wii Sports like title once they've gotten a taste of it. Clubhouse games could have been huge, but Nintendo decided to gimp it. And we'll see how they handled the latest Paper Mario in a few weeks... If Nintendo release the right games the system should easily sell more than 130m units.

Right now we have one Switch in our household. We won't buy a Switch Lite, but a "nicer" Switch (either a redesign with the better battery life of the latest model, or a beefier version of the hardware) would be a potential buy. 

2020: 70M (20M)
2021: 90M (20M)
2022: 105M (15M)
2023: 115M (10M)
2024: 120M (5M)

Something around 120M lifetime. I'm still more pessimistic because the low power hardware could be an issue the next years, so I voted 110 - 120M. If Nintendo releases a Switch Pro (New Switch XL), the lifetime sales should be easily above 120M.

This is what I said two years ago and I still stand by it.  Switch is for the most part selling exactly as I thought it would.  The only exception is that I thought it would be selling at this current rate about a year ago.  However I have no indication from the data to change my prediction.  Switch sales are still accelerating.

In the past two years a few more people have caught on to actually how historic the Switch will be as a console, but most people still don't get it.  Here is one question that most don't have a good answer for: "where are all these Switch sales coming from?"  It is tracking ahead of 3DS + Wii U.  In fact by this time in their life both the 3DS and Wii U have gotten price cuts and sales have signficantly started to slow.  Switch sales are still accelerating and it hasn't had a price cut yet.  It can't be just 3DS + Wii U customers.  Where do all these customers come from?  Also, Switch hasn't had a hit "casual" game of the magnitude of Wii Sports or Nintendogs, so the extra customers couldn't have come from the Wii/DS gamers who left.  Where do these customers come from?

When people start to realize where the extra customers come from, then it will be easy to see how Switch can sell 160m+.

Until Holiday 2019 to the present, I didn't find it likely at all that I could touch the Wii. Now, my mindset has changed. Now I'm pretty sure it will get around 110 million, but probably a few million under that. I voted 100-109.9 million. If the Switch does hit 110 million, it'll be just barely.