Turning 50 is an odd one.... You are drifting away from your youth at quite a pace - you are closer to retirement than your 20's.
Your kids are probably turning more independent and don't rely on you much, or listen to what you say! Your career may not be panning out as you would have hoped.
I was lucky, I already had plans in place to move house (to the coast) and start a new part of my life - new job, kids left / leaving home. I would recommend making big plans like this. Ahead of making the change you have something to look forward to - which is key. When you make the change a lot is new as it is like being on a permanent holiday for about 3 years.
Not for everyone, I know, but my twopenneth