How does the use of UMIs impact input DNA quantities?

Unique molecular identifiers (UMIs) enable PCR/sequencing error removal and high accuracy single molecule counting analysis. This is achieved by grouping identical sequencing reads containing the same UMI in a single family and creating a consensus read. Therefore, a certain amount of PCR duplicates is required to take full advantage of UMIs. However, downstream bio-informatics analysis can also be conducted ignoring the presence of UMIs.  

Depending on the need for UMIs, the following DNA input quantities are recommended: 

-1-100 ng of input DNA is recommended when wanting to take advantage of UMIs 

-100-1000 ng of input DNA is recommended if UMIs are not required or when preparing PCR-free libraries