I think this is especially true in your day to day quest to live a healthier life.
As I move through life, I conquer one challenge, only to find new challenges to conquer.
Take for example eating at work - this is a continuum on my challenge list.
Working as a nurse, we don't have opportunities to leave and go eat. Some days we are hard pressed to get get a break to eat! So my first challenge as a diabetic was to find healthy snacks and foods to have handy. I bought a insulated lunch bag, and brought healthy snacks and lunch options. Ideally I should eat something every couple of hours, so I bring handy things to eat that are low carb and not processed.
Great. I put my lunch bag in the back fridge, and it worked.
Then that fridge broke, coinciding with the holiday season.
Now my bag went into the front fridge, in the room with all the crap - candy and cookies for sale, baked goods and candy from patients and staff.
I'm great unless I see the tempting foods. I don't have them at home, for example, so my eating at home is healthy.
Boy did I fall off the wagon yesterday in Christmas leftover land. And I had horrific blood sugars to show for it.
Time for a new fix.
Obviously I can't be in the front break room. At all. My discipline around Godiva is nil.
Today I started my new plan. I put ice packs in my lunch bag, and an assortment of things I enjoy eating that are low carb. My bag is sitting by my feet, and I'm not stepping toe in that tempting break room.
Lesson learned. Find a fix that works for you. Don't make excuses - own up to your areas of weakness, and find a solution! 
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