How probable is it to make typo & send [BTC] to a wrong address?

[fredthegambler]

You might want to use copy and paste. That way you cannot mis type your address.

it is 1 million times more likely copy the wrong address than to mistype and still have a valid address.

But paste an invalid address is unlikely if you pay attention

That is right, the thing is you need to be careful when you write down/copy your address. Check it once, check it twice and do not rush things up!