This is very aptly described in the morning reading on day 5 which is about getting the balance of practice right by being relaxed, but working with Right Effort.

People who leave the retreat prematurely are sometimes referred to as 'those whose practice was a little too loose'.

If you have a naturally tight style, it is worth making the effort to let go a little more. But this may come naturally as part of one of the experiences of meditation.

If you have a naturally loose style, you may naturally find yourself tightening a little more if you can be mindfulof your experiences.

People at either extreme will probably get less from the retreat than those who practice in a balanced way.