PSA: Always keep at least 1 DOT in your Polkadot wallet or you will lose everything!

Polkadot is a bit strange in many ways and most of it is not explained in a way that is obvious to non-programmers.

(For example, I could not figure out why I couldn't see my funds in my wallet until someone explained to me the difference between polkadot. js the app/site and polkadot. js the extension. This was not explained in the official documentation, which shows how to set up the extension, but doesn't mention that it is not a full wallet, like MetaMask, Phantom, Temple, etc.)

But the "feature" of reaping deserves special attention and should be understood by anyone (potentially) involved in the DOT ecosystem:

If you have less than 1 DOT in a wallet all the coins in that wallet will be burned and gone forever.

This means that if you have alt-coins in that wallet as well as some DOT and you decide to send that DOT to an exchange for trading, you will lose all your alt-coins, no matter what they are worth. Unless you leave at least 1 DOT behind.

Just something to be aware of.

EDIT: A few commenters have pointed out that I may be wrong regarding the burning of coins other than DOT (or KSM, when on Kusama) and that only the DOT (KSM) gets burnt, whereas other coins can be retrieved once the account has been activated again. I cannot confirm this, as I have not tried it out and the official documentation is not super clear on this, in my opinion.

In this document it says:

"On the Polkadot network, an address is only active when it holds a minimum amount, currently set at 1 DOT (and 0.0000333333 KSM on the Kusama network). This minimum amount is called the Existential Deposit (ED). (...)

If you are sending all (or almost all) of your funds out of an account, which will result in the remaining balance going under the ED, the account will be reaped and any remaining funds will be burned

An account can be reactivated anytime, however, this will not bring back any previously burned funds"

This, in combination with information I got on Discord, made it sound like the only currencies that can serve as ED are DOT and KSM, but that everything gets burnt when the DOT balance drops below the ED. If that is not the case I am happy to be corrected. But I do think that this should be made much clearer in the way the documentation is written.