These are the main factors to consider when choosing an appropriate DNA extraction method:

• Sample type: The most important factor you’ll need to consider when choosing a DNA extraction method is the type of sample being used. Are you extracting DNA from bacterial cells, animal tissue, blood samples, saliva, soil, plants, or feces? Each sample type requires a different method for most efficient DNA extraction.
• Plasmid DNA vs. genomic DNA: Different protocols exist for isolating plasmid DNA versus genomic DNA. The main differences between the two lie mainly in the lysis processes and some buffer formulations.
• Downstream applications: The DNA extracted must meet the downstream application requirements in terms of purity and quality. Make sure to choose a DNA extraction method that will give you the purity and quality of DNA for your downstream application. 
• Yield: The DNA yield required for your downstream application is another factor to consider. The DNA extraction method you choose should meet the yield expectations for your purpose.