The NCT is not a huge indication of how roadworthy a car is. I am a mechanic and have seen plenty of items that should of failed and the car passed, on the other hand i have seen plenty of things fail when they have nothing wrong with them. Such as my dads car about 2 years ago, i focused the lights on it and it failed, then i rechecked them and it failed. rechecked them again and it passed. is very hit and miss.
My current car has no NCT (out by 1 year) but i know myself that the car is safe. I'd rather know myself the condition of my car by checking it regularly than some piece of paper that says it was ok on a certain day. The one main reason i may put it through the test is that when selling it people look for nct and will make it alot easier to sell.