For large projects I would assume that 1,000s or 10,000s of images could be used to map an area. Is there a limit on how many files can be processed within a project?
I am not sure about the maximum limit but I have processed 15,000-17,000 images for a thermal project before as for the rgb’s I have done around 2000 images.
A rule of thumb is that if you have more than 2000 images at about 12MP, splitting the project into subprojects for the processing is usually a good practice. There are some tips in this article: https://support.pix4d.com/hc/en-us/articles/202558579
RAM can be an issue for very large datasets. Also, if you have several flights in different conditions, it can be tough to reconstruct too. More here: https://support.pix4d.com/hc/en-us/articles/202560909