The key is to find what works for you.
You need to find a time that means you will actually fit it in. It is so easy to have a day so packed full that finding even 20 minutes seems impossible.
I find it best to get up and meditate first thing in the morning, well before the rest of the house is awake. This means that I don’t get disturbed and that I actually fit it in. At this time my mind is alert and I carry the benefits over to the rest of the day.
If I leave my meditation until evening I find that my mind is too sleepy and i really don’t get the most out of the session.
Routine helps, the mind and body love routine and if you are able to get into a routine you will reap the rewards.
Daily meditation certainly gets the best results. It is like any new skill, the more often you do it the better the results.