‘Better the devil you know’ – staying in one bad situation instead of moving because a new situation might be just as bad, or worse.
Don’t take risk, put up with the bad situation because at least you don’t have to face a new one.
Perhaps, it is sensible advice.
But not always, sometimes, the right thing to do is to move away. To seek the unknown devil. You never know, maybe the unknown devil won’t actually be that bad.
I suppose it is also important to make sure that the devil you know is really a devil before you leave it.