NullReferenceException After A Few Hours?

Alright, so I have this very annoying problem that keeps occurring after an hour or so. I have 3 3D Text Objects that are being changed via the Update() method, and everything works great until after a certain amount of time that causes this line right here:

    GetComponent<TextMesh>().text = "Fuel: " + playerScript.Fuel.ToString("f1") + "%";

And 2 others that are closely like it to return a NullReferenceException. I can’t find a solution once it occurs, UNLESS I restart Unity, which is making absolutely no sense whatsoever. Anybody care to shine some light on the subject?

can’t help too much without the rest of the code and error. For example I don’t know what is updating playerScript.Fuel, or if playerScript is changing at all.

It does seem though that your playerScript variable changes to null, as its the only thing that can be null! So make sure that it isn’t being set to something that is null.