What is the minimum number of nails required to properly secure small lengths of tack strip to a subfloor?

To properly secure small lengths of tack strip to a subfloor, the required minimum is two nails. This ensures sufficient holding power to keep the tack strip in place, allowing it to grip the carpet adequately once it's installed.

Using only one nail might not provide adequate stability, as the tack strip could shift or come loose during or after installation. Additionally, using more than two nails, such as three or four, could be excessive for small lengths of tack strip. It tends to complicate the installation process without providing significantly greater security for the strip. Therefore, two nails strike a balance between stability and practicality for securing the tack strip effectively.