20 machines in 2-3 months is quite impressive! Now, as for the questions...

Right now I have 192 typewriters. The last one is a Königer Eurographic, and shortly the number will be reduced to 191 because I have a Corona Special ready to be given to my uncle. I´ve never sold any of my typewriters (in fact I´ve only sold a mechanical calculator, a Summira 7) and my repairing abilities have improved over time. Collecting since 2012 and still going on!

My favourite machine... If I can pick two of them these would be the one I started collecting with, my grandfather´s Olivetti Linea 98 and the Continental Silenta. The first has great sentimental value and at the same time its fast and suits my typing better than anything else I´ve tried so far. The latter is the perfect balance between engineering and performance while still looking awesome.
 

Thanks for the input! I´ve been thinking about it and finally a decission has been made:

No Dremel for now.

I think I won´t use it enough to justify the expense. Yeah, it could be useful in some cases, but not enough to make me buy it. Buffing discs can come in handy, but as far as I know they don´t last long and the wet foil is working wonders on my Smith Premier 10-A. I´m testing various things on that poor thing, and so far I haven´t needed a Dremel for anything. And should the need come, I can scrounge a Dremel from a friend for a while. Even if the risk of damaging something is not that high, the problem is that I don´t really need it (even if it could come in handy).

What I´ve found EXTREMELY useful is an air compressor. I´ve finally had it repaired and it´s saved me a lot of time. What it asks in return is a good headache. It´s so noisy!

The Olivetti Lettera 32 is a great choice. Affordable, light, sturdy and overall great quality. I´d go for that one
I was given a Nakajima 8000 when I was 10 or 11, and it´s still there, but I wouldn´t reccomend it. As for truly tested typewriters, I´d go for the Olivetti Studio 44. My grandpa had one, and my dad and his 4 little brothers used and abused it for years. Now I have that typewriter, and it´s alive and kicking! The bad part is the size, weight and availability.

I try to name my typewriters, but only about one third of them have "their" name. I mean, I try to give them a proper name, something that says about the machine or how I perceive it. In fact, finding a name for a typewriter is quite entertaining. Some typewriters almost shout it in your face, but others remain silent. If someone has read Bleach, it´s a bit like getting to know your Zangetsu.

For example, right now next to me at my workplace I have a little army of them, and the names go like this:

- Sedens (Smith Corona Standard)
- Metropolis (Underwood All-Electric)
- Bug (Olivetti Valentine S)
- Asterion (Patria)
- Eneomaos (Remington Vertical Adder 21)

And apart from these, another 7 unnamed machines.

Let´s see... First the usable ones:

1909 Fox 23.



In PERFECT condition after being serviced by Pascual and Alberto. A true pleasure to type with!

1915 Remington 10:



Surprisingly, it came in good condition. Somebody must have taken care of it at some point, because even the ribbon is fine. Another joy to use!

1916 Underwood 3:



Not usable at first, but it´s one of these machines I feel proud of because I made it work! I must say it was easy-peasy, mostly owing to the legendary durability of the Underwoods. Not as satisfying to use because its so... modern. Works flawlessly, and for sure you wouldn´t say it´s 100+ years old.

And as for non-working machines...
1912 Smith Premier 10-A. Everything works fine, but it needs thorough cleaning, a new ribbon and a new spacebar. I think I can tackle this one on my own.
1913 Bennett Portable. A Bennett will never be usable, period. Mine is fine as it is, because everything is in place except for the missing paper bail.
191X Diamant: A paperweight. I´m not sure about the date so it could be newer than other 1910´s typewriters I have (Adler 7, Royal 5, Continental Standard), but it doesn´t work and I´m in no hurry to have it repaired.

And finally, a special mention for a parts machine 1914 Underwood 5.