I was recently at a retreat where the retreatants were surprised to learn that samadhi was something you could settle into at any moment - as opposed to some mental state that you had to work yourself into by some feat of mental endurance. So, let's enjoy the knowledge that you can drop into the large welcoming cushions of samadhi whenever you feel the need - just by tuning into the sensations and dropping in. There's an ocean of feathers in our minds whenever we want it.
There's a catch though. We have to know what it is before we can tune into it. We need to know what the mental factors feel like when samadhi is present, otherwise we are groping around for things we cannot see. So, it requires cultivation and practise to open up to the giant sofa of the mind - but this is a question of lifestyle persistence rather than a supreme mental effort. Plump the cushions, open the mind and drop right in.