Thickness of trading card protectors

Perhaps there are some trading card collectors in the forum who can answer a question or two for me about the thickness of trading card protectors.

A colleague is putting some symbols, vocabulary words, etc on card stock for her students to use. The cards are then placed inside the kind of protectors used by trading card collectors. We are currently using individual protectors for each card not the ones that hold multiple cards. We need the protectors to be somewhat durable because they sometimes get stepped on, thrown about etc.

Here come the questions:

1. I've seen protectors ranging from about 75 point up to about 180 point or so. Am I correct in assuming that the 180 point protectors are thicker, and hopefully more durable than the 75 point cards?

2. Because one side of the protectors are open we can swap in new/different cards as needed. Any other ideas for similar items that might work better than what we are using.

My guess is that you have to strike a balance between protection, cost, durability, flexibility, etc.

But, what about straight-up laminating the cards once they're made? One thing that would work against you here is if the cards are on the thicker side.

We thought about laminating the cards and do have some that are laminated. We tend to laminate which can sometimes be time consuming if there is a backlog things waiting to be laminated. We tend to laminate cards that will be used over and over or with all of the students. The sheet protectors are used for cards that are somewhat individualized or will be used for just a short period of time.