I've tried a bunch of life hacks - I'm going to be using that term loosely - and I quit using almost as many. Here are six hacks/technologies/products from the mundane to the profound, that earned their keep.
1. Hairband 'wallet'
I carry plastic cards and sometimes notes, never coins. I found traditional wallets bulky and fiddly to open and close. They break too easily, and are expensive to replace. The hairbands I steal from my girlfriend don't have any of those problems and they hold my cards together really well!
2. Keep your eye on the opportunity cost!
When deciding whether or not to do a thing, I've gotten myself into the habit of consciously considering its opportunity cost. What could I be doing if I didn't do this new thing? What's the value of that forfeited thing to me? What kind of intrinsic satisfaction would I derive from it? What would the expected financial compensation be? What would its effect be in terms of changing the world in the way I'd like? Does the new thing really weigh-up against that?
Most of these aspects can't be quantified but just consciously considering them and inspecting my intuition helps me a good deal. The result has been that I've been more able to (for instance) avoid unproductive exchanges online, and more able to say no to new demands on my time and energy. The deployment of my limited resources is governed a good deal less by limbic spasms these days. I'm getting less lizard-like!
3. Soylent sucks less than lunch
Meal-replacement shakes, I tried a few others, but so far Jake Shake is my favourite (sorry 
If you routinely enjoy delicious, varied lunches with sparkling conversation and laughter then just keep doing your thing. On the other hand, if you're not a food romantic, have a lot to get done, and aren't spooked by the dystopian feeling that haunts space food, give it a try.
4. You, and I, really do need a budget
This one's thanks to @cryptoctopus.
YNAB (You Need A Budget) is a non-traditional budgeting app/system. My income is all over the place, which made using standard budgeting solutions difficult. YNAB works in reverse to most budgeting systems. Rather than beginning with the costs you think you make each month, you begin by entering what your bank balance is right now. Then you assigning 'a job' to every Dollar (or Euro in my case).
It took me a few hours for the pieces to fall into place but I'm glad I found this system. Finances are already a good deal less stressful.
5. Mosquito zapping racket
If you've never used one you might be put off by its daft looks; like something a circus clown might pull out of his pants. Don't be fooled! If you've ever tried to swat a mosquito with any other object, and failed (or finally succeeded after 45 minutes of chasing around your bedroom while you were supposed to be sleeping) get one of these.
If you see a mosquito sitting somewhere, you pick up the racket, hold the button and passionlessly, with inner-peace, move the head towards the target. It touches the wires and is electrocuted with a little flash. Remove mosquito rage from your life. Consider getting insect screens for your windows too.
6. Nonviolent communication - Echo the other's grievance
This is a suggestion that belongs to the Non-Violent Communication school of thought, but already works great all on its own. If someone's upset (especially when they're upset with/at you), take a moment to hear them carefully. Don't try to defend yourself, instead reflect back to them what you believe their grievance is, and how you think it's making them feel. This often has a wonderful deescalating effect that makes it possible to talk through the problem and both feel better afterwards.
The person I most often have the chance to use this technique with is my 2.5 year old son. It's strikingly effective, and works with adults too.
NVC suggests that however the other person expresses themselves, we focus on listening for the underlying observations, feelings, needs, and requests. It is suggested that it can be useful to reflect a paraphrase of what another person has said, highlighting the NVC components implicit in their message, such as the feelings and needs you guess they may be expressing.
What hacks are helping you these days?
I'm Tomasz Kaye. I made George Ought To Help and other pro-liberty propaganda films. You can support my work on Patreon.com.