It depends on the source media and the effects applied, as well as your specific computer specs and hard drive setup..
Just some supplemental thoughts....
What is the destination for your Timeline content....export to file saved to the computer hard drive or a burn to disc product.
Just one example of extra things to factor in....
If you see a Bitrate of less than 8.00 Mbps in the burn dialog immediately before hitting the burn button, you are probably getting to the too much level of Timeline content for this particular project and its goals.
For the moment focusing in on the burn to disc DVD-VIDEO on DVD disc. If you use a standard DVD disc, the disc labeling will
include 4.7 GB (120 minutes). But in reality, that 4.7 GB is 4.38 GB. So, given you have your Timeline content ready to go to burn to,
you have your DVD disc in the burner tray, and you are in the burn dialog....you look to the Quality area of the burn dialog and read
the values for Space Require and Bitrate. (There is a check mark next to "Fit Content to Available Space".)
Even though the burn dialog shows Ready, a Space Required = 4.38 GB and Bitrate of anything less than 8.00 Mbps means
that the program is trying to make the fit by lowering the Bitrate to lower the file size. But, lower the Bitrate, the lower the quality.
One popular generalization is to try to keep within 90 minutes for the burn to DVD-VIDEO on DVD disc.
As a point of trivia, you can actually place about 23 hours of content of the Premiere Elements timeline after which it will accept no more content.
Never tried to edit or burn that content.
The question of how much to bring into a Timeline has many offshoots.
If you have some specifics as to computer resources, import formats, destination preferences, file size requirements and the like, we
could discuss Timeline content ramifications specific to your situation.