Default "No Sim Card" - should I be worried? Happened twice today.

does the sim card gradually die, or is it more like one minute you're fine, the next you need a new one?

a couple times I have gotten "no sim card," but a reboot took care of the problem. i'm using the zerolemon battery so maybe that has deformed the sim slot?

it has only happened twice...and i'm wondering if this means it is only a matter of time before i'm screwed...or is it more likely i would be able to do something that would allow the sim card to be read properly because the slot is damaged? i read something about putting a piece of paper/cardboard in the slot, but i haven't looked much into it and hoping i don't have to...

thanks