I am so with you!
I had mitral valve repair in June '06. My valve had gone from bad to worse almost overnight. My cardio said I was leaking moderately in April the previous year--twelve months later, my valve was in dire need of surgical intervention. My valve, though, was leaking from birth. My valve is myxomatous, which means that at some point in my life, I was going to need surgery.
It does seem like many "repairees" here have needed replacements after repairs, and that does scare the four-letter word out of me. I know you're more recently out of surgery than I am, and like you, I was pretty anxious about the vague threat of re-op in the months following my surgery. Although, like I said, having to have another valve surgery scares me, it doesn't frighten me as much as it did in, let's say, December 2006.
Anyway, I think the skill of the surgeon, the condition your valve post-op, how your heart heals, scar tissue, and all that lovely stuff really determines the long-term outcome of your repair. I've read that anterior leaflet (the front) repairs have a higher rate of re-op than posterior leaflets. There's a journal article about it on the American Heart Association website. I'm not sure why, but I think it's because the front part of the valve has to withstand a lot more pressure than the back one. I had anterior leaflet repair myself.
Don't concern yourself too much with whether or not you'll need another valve surgery. Just focus on living. That's what I try to do, not always with success, but I do my best. My thought is, if you need another surgery, then you do. I really don't think there is anything you yourself can do physically to prevent another surgery.
Take care of yourself and focus on the positives: you're alive, you made it through valve surgery, and you're growing stronger and healthier every day!
Of course, if you have any concerns, always address them with your cardio. Or you can call mine!
Debi (debster913)