What are things you can’t go without?
I lived for 2.5 years from 2015 until about 2018 just out of a carry on bag and using Airbnbs. So I know specifically what I can't do without even at this age in my life.

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1. A bed
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2. A towel
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Sort of like the advice in Hitchhiker's Guide to the Galaxy
3. The stuff in my carryon bag which is:
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4. 3 white t-shirts and 3 pairs of underwear
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Note that both of these are for sale for around $14 in CVS so I would rarely do laundry and just throw them out and buy new ones.
5. 2 pairs of black pants and 2 white button down shirts
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6. Sneakers
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7. A laptop and mouse and phone and charger
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8. A jacket
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9. And that's about it.
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10. I would order food in every day. And...
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I would use whatever other furniture the Airbnb had. Every morning when I left whatever Airbnb I was staying at I would not leave any of my things so it was as if I had never stayed there. I'd usually work in a cafe. So I'm not sure I needed anything else.