Not knowing anything about fountain pens, I was surprised when I read in a post a while back that a nib has to be used and worn by the user before it gets a comfortable feel. Learn something new every day!
That may have been true in the early days before "iridium" tipped nibs, and when people wrote for hours each day. With modern nibs, paper, and writing habits, a nib wouldn't "wear in" for many years. What mostly happens is that the user adapts to the pen without realizing it.
I have several vintage pens, and they all write just fine for me; no sign of any of them having been "broken in" or "worn in" despite having obviously been used heavily.
The importance of matching nibs and feeds is due to a lack of standards from one manufacturer to another, though minor differences in curvature can be accommodated if one owns a nib block and knows how to use it. Many modern nibs have tabs and/or notches that interlock the nib and feed, so only that type of nib will fit that type of feed.
More important is matching the feed with the size of the nib's stroke: a feed for a fine nib won't provide enough ink to a broad nib of the same type. Pre-assembled, screw-in nib units avoid this issue entirely, but where's the fun in that?
"Iridium Point Germany" used to mean what it says; nowadays it generally means "Chinese" and may or may not be a good nib. Some IPG nibs have no tipping (the "Iridium" part) at all.
If you want to use *good* nibs, buy Bock, JoWo, Schmidt, or the ones Brian (Edison Pen Co.) Grey sells.
Oh, and modern steel nibs write every bit as well as gold nibs, but some people won't accept anything but gold. Steel nibs tend to be very firm ("nails") in comparison to gold, and well-suited to folks used to ballpoint pens. Gold nibs are usually a bit more flexible and have a "softer" feel against the paper. They're more easily damaged by people who aren't used to writing with a fountain pen, though.
