I've been doing layouts for years, always using .tifs when placing artwork. I recently received a job (started by another designer) where they were placing the press quality pdf's directly into the layout without converting them to .tifs first. I always thought that this was "taboo". Do any other designers do this and have you had any issues using the pdf directly in layouts? Thank you!
If the pdf is self contained and, well prepared it should be no issues.
It is a common practice when making layouts of magazines where peolpe send de adds.
Always there are things that could go wrong. But make a test, prepare some PDF, make a layout, insert them and at the end, prepare another PDF with the other PDFs inside. If you can see it correctly on the adobe reader, it should do fine.
Some aditional info.
Use the proper file on each case, for example use PSD, or inclusive good quality JPG for photos or bitmap images, AI or PDF for vector files.
A PDF is a good potion where you have embeded text with embeded fonts.
You can convert it to tiff if you need interaction with an image, shadows, etc, but it is a good idea to keep the original file format when possible.
Remember that InDesign link externally this files so any edition made on them can be updated on the final result, this can be an aditional reason to use a PDF while doing a layout.