I was guilty of apostrophe abuse until recently. I have made it my mission to stop using them for pluralizing abbreviations, numbers and acronyms. VTF--3s instead of VTF-3's for instance...
Pogre, this is not specifically directed at you, rather your post was the most clear about questioning how apostrophes should be used.
Do you have a reference on that?
I am pretty sure that is an appropriate use of the apostrophe!
If I were to say "I enjoy listening to my VMS-8s", you would have little idea of whether the model number is VMS-8 and I have more than one or if the model number is "VMS-8s".
You would certainly not write "Count how many is there are in Mississippi" vs "Count how many i's there are in Mississippi"!
Okay, I did some research on this and it does seem that there is a trend to reduce the use of the apostrophe where not needed for clarity.
For example CDs is preferred to CD's (although CD's is considered a valid option - IOW, the reference I read was not absolute about NOT using an apostrophe here).
However it does specify that it is preferred to drop the apostrophe when the apostrophe is not needed for clarity. Obviously, for something like CD there is no risk of confusion. However, I would argue that for my PSA XS-15se's the apostrophe provides a useful distinction and would consider it wrong to write "for my PSA XS-15ses the apostrophe provides ..." because it makes it clear that the second s is not part of the model number.
Your VTF-3's are a common enough model for the regulars here to know, and the fact that all other letters are capitalized would help others guess that the s is not part of the model number, but they are guessing. So I would consider that a gray area!
However, I, personally, will continue using apostrophes as I have. I have always considered 60 old, and now that I am over 60, it is my privilege to be an asshole who is stuck in his ways (Wow! no censorship of asshole!),and I fully intend to exercise that privilege!
As a matter of fact, just to show you all what a belligerent curmudgeon I am, I will continue to write 70's instead of '70s, defiantly dropping the required apostrophe before the 7 (based on it being a contraction of
1970) while including the totally unnecessary apostrophe before the s! Ha! Suck it! Now get the f' off of my lawn!