Here’s an little Illustrator tip I picked up on.
I found that I needed to frequently copy objects from one project into another. But opening the original constantly was difficult since it was a 100MB+ file. It was the Healthcare building I designed in my Illustrations portfolio.
I found that if you take those frequently used objects and save them to that file’s symbol library, you can open that specific library from any other document via the Symbols Panel’s menu. If you open the Symbol Panel’s menu from the right corner, then choose “Open Other Library” from the “Open Symbol Library”, navigate to and select the illustrator file you are looking for.
When you open the file, only the symbols from that document will open as a separate tab. This is especially useful when dealing with large documents that use a lot of memory!