Odd Suica question

So, recently I was in Japan for 3 weeks. When I was in Tokyo I bought a suica card and was using it to get around. I then headed over to Thailand for two weeks. The day I left Tokyo for Thailand, I swiped my Suica card at a JR station near where I was staying and travelled to Shinjuku station to catch the N'EX to Narita. I had a ticket already purchased for the N'EX. Two weeks later I returned to Tokyo for just one day and night as my flight back to my home country was from Narita and not Thailand. My Suica card wouldn't work and I figured that it was because I never swiped it a second time on the day I left. When I got to Shinjuku to catch the N'EX I just went straight to track #5 from within Shinjuku station. I had to go to a JR office and get them to reset the card because I still had money on it and wanted to use it.

The JR employee didn't really care. He asked what station I entered and I said "Well two weeks ago..." and he just said, "Daijobu" and sent me on my way.

So, my question is how do you avoid having your suica card locked if you are travelling to Shinjuku to catch the N'EX? Should I have gone out a gate at Shinjuku swiping my Suica card to complete the transaction then entered back in using the N'EX ticket? Seems like a lot of work when you can just dash to track 5 once you get off of another train. Is there another way?

You simply swipe it when entering the gates at Shinjuku Station and swipe it again when leaving the gates at Narita Airport.

Snooch,

If you had already bought a ticket (and seat reservation) for the Narita Express from Shinjuku, you should have left the ticket gates at Shinjuku using your Suica card and re-entered using your NEX ticket. If you don't, you are basically paying twice for the same trip (Shinjuku to Narita Airport). Ideally, you should have just bought a limited express supplement and seat reservation for the Narita Express, enabling you to use your Suica card all the way to Narita Airport without any fuss.

I see, with "ticket" you referred to an actual base fare ticket. I thought you referred just to the limited express supplement ticket and wanted to use your Suica card for the base fare.