This is a great thread.
My best life hack is my lifestyle.
I live simple. Very very simple.
I own the land, no mortage, no payments on anything, all is done on cash only basis. Heat w propane, and wood fire, well water, pure as anything, grow my own organic veggies ( save all sorts of money)
My husband built the house by hand over three years, with the help of friends. The house is designed for saving energy and retaining heat, it is dug half into the ground to protect from freezing weather/heat loss insulated like crazy, I dont spend much to heat it. Have a huge russian indoor fireplace that is from basement to roof , and it heats the whole house.
I only have stuff around that I made or other people made for me- real art, real pottery, ect. I try not to buy junk, and the less money I spend the less I have to earn, the more free time i have to do what I want and the more independent I am. I try to think carefully before i spend money.
I live clutter free- less stuff makes it so eay to clean and visually less distracting. I try to not get attatched to “stuff”
I dont have cable tv, only local channels.Dont have any membership fees.dues,or obligations, owe people nothing.
I trade stuff instead of pay money when i can-some of the house work was based upon trades for stuff I had already.
I try to buy local stuff that is made in America by local craftspeople or grown here.
I use it up, wear it out, make do, or do without.
summer exercize is just llife stuff, so I dont need to work out because life work is enough, Winter I have a stairmaster, though just shoveling snow is a workout.
My simple lifestyle allows me to live comfortably and safely on very very little money, as long as I am not stupid about buying stuff. I did do a major home renovation, but it was planned for over past 35 yrs and paid in cash and will keep me comfy the rest of my life and the home and land will go to my kids after to do the same.
this has freed me from being a ‘slave’ to rent and work, and I have the best gift, time to do what I want to do. The trade off is living in a lifestyle that some other people think is not as cool-small house vrs huge, ten yr old car, old clothing. I dont have expensive clothing/makeup/hairstyle/ but I look presentable, clean and well cared for, not like a wild mountaineer, because it is best to fit into society when out in public, so I do. At home, I just wear whatever.
I try to do more than two things at once, all of which are useful to me such as exercize=grow my own organic food=food that is less expensive and more healthy=less travel=more time
chop wood=exercize=less expensive=renewable resource=not dependent upon gas and oil prices=save money=more time
The trade off is long car trips when I want to get off the mountain.
Other hacks?
I dont do anything with a religious passion-so my simple lifestyle is not fanatical, it is just a tool, not essential, I do what is easier and less expensive but will adjust to simply have fun when I want to. So even though I live a very simple life, I still will drop money to have fun, go places, do stuff. I just save so I can do it.
take viamins
well water is best, and I drink it often and had it tested, it is perfect.
I am a vegetarian but eat sea food, and occasional dairy/eggs from local animals that are free range and loved, I know where my food comes from
I try very hard to only cook just enough food, not too much, so dont waste any, same thing with purchasing or picking fresh garden food, I only take what I will eat that day, so I preserve the freshness. I think this is a good hint because people waste so much food. The only time I change it is when I am preserving stuff to freeze/can. I compost.
Winter time I eat whatever, I dont always produce enough to eat all year long, and it dosnt matter, just buy local/organic/cheap when I am out
Over the years I am trying to reduce the amount of money I need until I need to spend little to none, and then I retire from working. I still have a lot to learn though, when I am lonely I tend to over eat and over spend. also, I have two dogs, one cat and two birds, they are expensive, so I will stick to one single pet after they pass away, ( I am commited to them for their lifetimes) I take very good care of them and it costs way too much $.
I know my life hack is different than some, but I suggest it because it seems to have freed me both financially and emotionally, and given me my life and time to do as I please, which is worth the trade. I am ‘off the grid’ in a way, or can totally be if I need to. 
simple=freedom
