How do I choose the number of PCR cycles to use for library amplification?

Cycle numbers for the endpoint PCR are indicated in the table in Appendix B of the Small RNA-Seq Library Prep Kit User Guide. For example, we recommend performing 15 PCR cycles while using an input amount of 100 ng. If starting with 1,000 ng input RNA, then 12 cycles can be used.
Depending on the small RNA content of the initial RNA sample, an additional 1 or 2 cycles could be added.