How do I prevent this from happening again?

Okay, I'm down another pound and it's been 9 days on very minimal carbs diet and working out. I won't be able to go the full two weeks, will be in North Carolina with Jim's family and it's Memorial Day weekend. I'm going to have some wine and just eat normal, but wise. Saturday will be day 13, so that's not too bad. But when I'm at my goal weight, how do I avoid this from happening again? I have to keep this in mind because I've been struggling with this 5-20 pounds for the last 10 years! Do I get on the scale every week? Do I start dieting again at 5 pounds over my idea weight? I know I'm going to keep exercising, running, strength training and staying active in general, but when times are stressful and time is short, what will keep me on target? That is what I have to keep in mind, maintaining this weight loss for years! Never seeing 150 again! How will I do it?