We are constantly in danger of over modeling and should constantly be aware of this. One rule of thumb I've adopted is to "model what you would see if you were standing across the street". A friend of mine told me this early on in my Revit career (thanks Bruce).
This basically means don't go into too much detail in your modeling, cover the finer details on your detail sheets, don't have over modeled families in your project etc.
The type of project may specify the level of detail in which you model. this goes a little beyond the basic LOD, it's more a case of LOM (level of Modeling).
For example, a hospital project I like to see a higher level of modeling as the project is so intricate and integrates to a higher level with the consultants. Whereas a simple interior fit out doesn't require so much modeling detail, here we can get away with less model content and refer to linework detail or even notes. Don't spend time on creating a family for when a simple placeholder or "generic" family will suffice.
You can burn up a lot of time spent on modeling what you don't need.
There are no hard and fast rules for LOM, it's just through personal experience and discussions with your Revit team, sometimes you have to reign them in and ask "do we need to go into so much detail?"
This comment can lead into a whole other discussion on exactly how much detail we need to put on our drawings.... for another blog posting...
Remember to modeling with a purpose in mind.
Purpose or Porpoise?