How often should weigh-ins be done?

My natural answer would be every day, naked before eating anything. But I know this isn't realistic or healthy. Soo...how often should weigh ins be done? Once a week? Every two weeks?

Also does anyone have recommendations for reliable scales? Are digital scales okay and how can I know if it is not working properly?

I don't own a scale.  I get weighed when I go to my doctor's office which is at least once a year; usually 2 or 3 times a year.  My guide is how my clothes fit and how I feel physically.  I can tell when I am gaining; I see the increased waist, I feel the tight clothes, I feel sluggish, I know I haven't been eating well.  I can tell when I'm losing; my clothes are too big.  I feel comfortable in the next size down.  Now I can tell when I'm within 5 lbs of my target weight and I have clothes that fit perfect when I am within this range. 

That is not to say that I don't occasionally step on a scale at a friend's house if it happens to be in the bathroom.  I don't worry if it is accurate.  I figure it gives me a ball park.  But generally, I don't focus on the weight.  I focus on trying to eat well, keeping active and living. 

I had always been slight (some would say underweight but I don't believe that was so) and then about 6 years ago I gained nearly 50 lbs.  I didn't really think about it until it dawned on me that I wasn't feeling a good as I had been and I was needing to buy yet another size larger.  The doctor's scale confirmed it. 

I revamped my approach to eating and my relationship with food.  I'm fortunate that I like many of the foods that are recommended and not a lot of the foods that are not recommended (I'm not a big bread and pasta eater for example).  I try to eat the majority of my calories at breakfast and lunch with a lighter meal in the evening.  It wasn't easy but it works for me.

My target weight is about 8 lbs heavier than my weight 6 years ago before I gained the 50 lbs and I'm ok with it because I feel very good at this weight.  By the way, my target weight is about 15 - 20 lbs heavier than the weight I had for a good portion of my adult life.  Also, I find that I gain much easier now that I am older than I did when I was younger. 

I don't generally consider myself on a "diet" but rather that I am giving my body the optimal fuel to live well.  I am not perfect and eat much that is not "good" for my body but as long as the majority of the time I am eating well, I don't obsess with it.  I could and that is the whole point.  I don't want to obsess and live my life focused on what I eat.  I want to eat to live not live to eat.  Enjoy and appreciate good food but relish the life it gives me.

I've found that it's helpful to take your measurements when you start. Some weeks you may not lose weight, but you lose inches. That's always encouraging!

Thanks for all the responses everyone. I'm really surprised to see so many people weigh themselves daily! I know that as for myself if I weigh myself daily I'm expecting to see a change happen every day of at least 1lb. or i'll be dissapointed..so if I follow my "healthy weight loss plan" I should only expect to lose 1.5-2 max per week..

I know about the weight fluctuations from day to day and I remember when I was in active weight loss in the past and weighing myself daily and I wouldn't have lost something or anything each day that I'd be ho-hum for the rest of the day. I guess i'm trying to avoid ANYTHING that might bring down my mood or motivation.

I guess I should take measurements as scrappycat818 mentioned, but I'm never sure if I'm measuring the right 'waist' or 'hips' since I have a very high waist, do i measure my natural waist or ...?