To give you a little background on our Imperial Library - It's primarily EUA created with very little remaining out of the box (OOTB) content. We actually started with the OOTB content during our initial Revit migration (5 years ago), but quickly came to the conclusion that it was lacking in many facets. It was fine for our pilot project, but that's where it ended. Content creation has been a 5 year project and will probably never end, but we're definitely over the hump. Content request by our staff have leveled off, but we still get one or two weekly. So, if you're a firm making the switch to Revit, be sure to consider the importance of quality Revit content. Don't get me wrong - Revit it AWESOME and we love it, but it's a shame that most of the content that ships with Revit doesn't have the quality or consistency required. Sorry Autodesk, but I don't think the content that ships with Revit has been updated for years...
The results below are a quick overview of our Imperial Library:
Total number of EUA Revit families: 6260
(FYI - Revit ships with ~1165 families out of the box)
EUA Revit families with a size over 500k: 35
EUA Revit families over 800k: 1
So as you can see, the majority of our families are less than 500k. We have only 35 families (slightly more than a half percent) exceeding 500 KB. Not even half our library exceeds 300 KB.We aim for a family size of 200k to 400k max if possible.
So, as you're browsing the web for Revit families and you think you hit the mother load- consider the file size and how this will impact your project. It will...
And remember - this is only one aspect of families that can affect your project's performance. Family complexity, formulas, nesting, arrays, etc. can also have a big impact - more on that later :)
Hope this helps!