Shield circuit from noise

I want to ask you if small holes for leds, connections or unshilded cables that go outside the shield box may compromise its function and how much.

Thank you.

Depends on the frequency of what's switching inside. Low frequencies have long wavelengths and need big holes, high frequencies have short wavelengths and get out small holes.
Are you trying to keep noise out? Or keep it from getting out?

CrossRoads:
Depends on the frequency of what's switching inside. Low frequencies have long wavelengths and need big holes, high frequencies have short wavelengths and get out small holes.
Are you trying to keep noise out? Or keep it from getting out?

Keeping the noise out. I need to sample signals, but i also need an indicator(led), buttons and an external device powered and connected(with 1 digital pin) to arduino inside the box.

You will need to be more specific about what kind of signals you are sampling, and in what environment.

I'd worry more about wires coming in from outside than I would a 5mm hole for an LED.

As for how much - how long is a piece of string?

polymorph:
You will need to be more specific about what kind of signals you are sampling, and in what environment.

I'd worry more about wires coming in from outside than I would a 5mm hole for an LED.

As for how much - how long is a piece of string?

Load cell, and the string is long about 1 or 2 cm.