How should the top of each strip of double-backed tape for a mirror be trimmed?

Trimming the top of each strip of double-backed tape for a mirror to a point is advisable because it facilitates a better fit and adhesion when the mirror is mounted. This pointed edge helps to create a more seamless transition between the tape and the surface of the mirror, reducing the visibility of the tape and minimizing any potential lifting or peeling that could occur at the edges. By tapering the end, the tape can also enhance the aesthetics of the installation, making it appear more professional and polished.

In contrast, options like trimming the tape square could create sharp edges that might attract attention or allow for easier detachment over time. A rounded trim, while slightly more aesthetically pleasing than a square edge, might not provide the same level of effective adhesion or clean look compared to a pointed trim. Leaving the tape untrimmed ignores the benefits of ensuring a better adherence and finish. Thus, the pointed trim is the most effective method for using double-backed tape in mirror installations.