It helps if we understand first why we are obliged to perform devotional service at all. If we have forgotten why we are making a particular offering, we will not be able to maintain our inspiration, but will gradually begin to think, “I have vowed to perform this activity, but I would really rather be doing something else.” This mentality of following the rules and regulations without being aware of the purpose behind them is called niyamagraha. We should be very careful not to follow rules and regulations simply for their own sake, forgetting the purpose behind them. For example, we may chant a particular number of rounds per day thinking that we are “safe” because we are meeting our quota; but if we do not have a sense of what chanting the holy name is meant to be about, we may think it doesn’t matter what else we do while we chant, and thus commit namaparadha. It is all right to feel commitment to our sadhana activities, but don’t perform them mechanically. Mechanical sadhana-bhakti does not produce bhava (pure spiritual emotion).
(LFD, Vol2, Purpose of Sädhana-bhakti, Pg 15, 4th & 5th paragraph)