It is not limited to these hands.
If You have a good pair or Ak yes
Generally, it is a bad decision, unless you hold AA or KK.
So I am going all in when I Have around 18 BB or less. Is this a good decision or a bad one?
18 BB means that if there's no ante you could have 18 rounds when you are a big blind.
But you must be a small blind, which is half of the bb so it means that U are gonna be there for 6,666 (BB+SB) rounds.
If 9 players are at your table, you can see 6,66x9 hands = 60 hands
I think this could be a nice example, why you can be patient and not to push over the first hand that looking good or acceptable.
So I am going all in when I Have around 18 BB or less. Is this a good decision or a bad one?