I have never regained a lot of weight. This has been my one and only major weight loss. But I'm going to chime in anyway.
It's that "fear" that keeps me on my toes and yes, ever vigilant. I think that fear is a good thing. We can never, ever get too complacent. Because when we do, weight creeps on and then creeps on some more. I totally agree with Nelie. That scale is a wonderful tool and we've got to use it. No avoidance. Catching any lapse before it gets to relapse, before it gets to total collapse. Gotta use those wonderful tools and strategies that we lost the weight with in place.
When I started my journey, I made peace with and ACCEPTED the fact that I was in this forever. No stopping. Just continuing. Forever. That's the difference between a diet and a lifestyle change or in my case a lifestyle OVERHAUL. Luckily I LOVE my life now, my energy, stamina, self confidence, size 4 clothing, yes - my looks, my doctors' visits, the outlook of my future. Not only do I love the rewards, I love the whole healthy lifestyle experience. I don't dread this. I don't find it a burden. I find it a joy and a pleasure to live this way. And I think this will be a huge factor in keeping the weight off. Learning to love the process.
Know, just really, really KNOW that you don't have to gain the weight back if you don't want to. It IS your choice. Just like it was your choice to gain the weight. Then like it was your choice to LOSE the weight. It will be your choice to maintain that loss as well. Choice. Choice. Choice. And as long as you keep on CHOOSING to keep the weight off - off it WILL stay. Remember as long as you work the program - the program works. Work it. Work it. Work it.