You can estimate life by matching material and use conditions. Metals like stainless steel and titanium hold crisp engravings for decades because the laser modifies or removes surface material with high contrast and hardness. Anodized aluminum keeps marks well if the anodic layer is thick.
Plastics vary widely: ABS and acrylic can hold marks, but intense UV or heat can cause color change or surface wear.
Wood and leather look good at first, but frequent handling, oil, sweat, and sunlight can soften edges and reduce contrast.
Depth matters. A deep mark resists abrasion. A shallow mark on a soft substrate will fade faster.
Environment is the third lever. Moisture, salt, grit, and caustic cleaners accelerate wear.
If you want maximum life, choose a hard material, increase engraving depth, use higher contrast settings, and seal or coat the surface where possible.
I test samples under the same stress you expect in real use before full production.