Over time, your sheet protector holes may begin to stretch and tear. This is especially true of trifolds which need more careful handling than single-page sheet protectors.
Because trifolds can be extended so far out and can hold three times the material (thus making them heavier), their holes are subject to higher stress.
The hole tearing can be delayed by making sure to "accordion in" trifolds before turning. Also it's a good idea to leave a little slack when clipping the trifolds (so that they're not pulling against binder rings).
When sheet protector holes DO tear, these plastic hole-reinforcing strips are great for extending the life of your trifolds. These are the only hole reinforcements I've found that will stick to sheet protectors.
Watch the video or read steps (shown below the video) for tips on how to apply them. (Sorry about the video quality 🤪.)
Separate strips (if not already separated)
Peel off paper backing to reveal sticky side of plastic; discard paper. Important: Use entire plastic strip and reinforce all three holes at once.
If holes are not centered on the width of the strip, apply such that the wider part of plastic is toward the outside of the sheet protector (see video above for more explanation).
Hold plastic strip slightly above the sheet protector to visually center the strip's middle hole with the sheet protector's middle hole.
Align the other two holes and lightly place plastic strip on sheet protector. Note: If misaligned, lift up plastic strip and try again.
Gently smooth plastic down outwards from the center hole. Press firmly along the entire strip to ensure strong adhesion.
A few other thoughts. The ends of these strips can be cut if they're too long to fit on other sheet protectors.
These can be applied on top of previous reinforcement strips. You can also put them on the opposite side from existing reinforcements.
Finally, I find it easier to apply these against a solid-colored background. My kitchen counters have a spotty pattern, which makes it hard for me to see and line up the holes. I use a thin, solid-colored, plastic cutting board to make it easier.