I like this thread.
In no particular order:
Got divorced.
Stopped doing Xmas except for children's presents. (Saved loads, no indigestion, feel healthier, only see people I like, no boxes of crap decs in the garage).
Stopped using Amazon.
Stopped buying Apple tech, definitely made life easier.
Deleted everyone off facebook, made the profile private and just use it to sign in to websites.
Got rid of the tv and just have netflix. One of best decisions I ever made.
Learned to use a slow cooker, total game changer.
Stopped using a handbag, just have a coat with zipped pockets for essentials, saves about 30 mins each day on school run and going out.
Schoolbags ready by door the night before.
Lanyard for house keys.
Delegated 1 boring house chore per day to each teen dc: if they don't do it, the mum taxi goes on strike. It gets done.
Stopped buying books and found Blinkist. Feel a bit better informed and no guilt about having unread books everywhere.