An important assessment to complete at the beginning of your project is to determine if you have the time and resources required.
How long do systematic reviews usually take to complete?
Systematic reviews are often more complex than many researchers realize and so they underestimate the time involved with doing a systematic review. A realistic expectation would be 6 to 12 months, and perhaps longer, depending upon your team.
How long should we plan to spend searching the literature?
A comprehensive search uses multiple databases to find the articles needed plus it searches the grey literature sources (clinical trial repositories, conference proceedings, unpublished literature, etc.). You can expect hundreds if not thousands of results from all of these sources. Most guidelines suggest the search protocol can take 1 - 5 months of development for a robust systematic review.