Out of interest, how often do people weigh themselves? My wifes on a plan with something called "Noom" and it suggests weighing everyday, with some evidence pointing to the fact that even though some fluctuations/increases will always happen from day to day, it keeps your mind focussed.
I tend to do it once a week, i'm trying not to become obsessed about it, same with calorie logging, if i eat some grapes or have a milky coffee i won't add it as i know i'm still generally in a deficit.
I weigh myself at the same time every day and log it in MFP. I use another app called Happy Scale (which pulls these numbers via Apple Health) to monitor trends over the weeks/months rather than getting obsessed with daily values. This becomes more valuable after a couple of months of data as you can see a rolling 30 day delta which smooths out any short term blips. This shows I have a +/- 3-4lb weekly range so as long as I am not straying outside of this I do not pay much attention to the daily number.
I am reasonably careful with logging cals, but a meal we eat regularly I will create just copy rather than weighing everything each time. I do try and log everything I eat just for consistency but yes the odd crisp I pinch doesn't get logged

I also check waist measurement and body fat percentage (using caliper method) once a month.