PBK said:I would say that there are at least seven good reasons to revisit even well-worked sites.
1. Heavy rains have saturated the area, enhancing conductivity.
2. Significant erosion has occurred due to storms or flooding.
3. Repeated hard freezing and thawing has resulted in major "frost heaves."
4. Landscaping has removed old shrubbery, fences, ground cover, etc.
5. Topsoil has been removed, or deeper layers turned, by heavy machinery.
6. You have new equipment which can detect targets previously out of range.
7. The area is scheduled to be paved, built over, or closed. Last chance!
stoney56 said:I think PBK pretty well summed it up. But also there is the changing your detector settings and coming back at a different angle.