How many amps do I need in a corded string trimmer?

Across the reviewers we read, 3 to 4 amp models (often 10-13 inch heads) handle light, regular trimming on small lots, while 5.5 to 6.5 amp models are the consensus pick for taller grass, thicker weeds, and bigger yards. Higher-amp units cut faster and bog down less, but they tend to be heavier and louder.