My wife, Malea, is an excellent writer and thinker. She has spent much time contemplating and practicing the disciplines and here is what she thinks about them:
Spiritual Disciplines: Described and Explained
Spiritual Disciplines aid us in becoming more like Christ and less ruled by our flesh. In other words, it is a way to use our bodies to put on the fruits of the spirit (love, joy, peace, patience, gentleness, kindness, goodness, faithfulness and self-control) and to free our lives from vices or sins. (Pride, envy, anger, laziness, greed, gluttony, and lust, just to name a few).
Any soldier or athlete has different disciplines he uses to become better at his particular activity. The Christian life is the most fundamental part of who we are and so it makes sense that we ought to “train in godliness” with even more enthusiasm and fervor than in any other activity. God made us to be a certain sort of person—one who is constantly yielding to Him and yet becoming more and more himself (with the personality and the gifts God has given). The fullness of joy, for a human, is only found when we “put off the things of the old life” and “put on the character of Christ.” We must, like Paul, “beat our bodies into submission.” (1 Cor 9:27)
It is important to understand that the things we give up for the purpose of training our bodies are not bad in and of themselves. They either have too much control over us, or are a way to gauge how strong certain desires are in our life and how much they control us. Eating is not a bad activity, neither is dressing nice, nor making a lot of money, but it may be good to give all of them up at different times to see how much they control our lives.
Also, different disciplines may be more or less helpful for different people based on our various temperaments and areas of struggle. Even within ourselves, the sins each of us needs to master in our lives will most likely change over time. Younger men may need to fast often to overcome lustful desires, whereas a middle aged man may need solitude from his busy work schedule to learn to be understanding towards his wife and children, (hold his temper, set the direction of his family) and an older man may need to overcome his grumpy desires and speak kindly or commit himself to study of God’s Word. Within our lives, God takes us through so many different circumstances and we should constantly be looking to cultivate godly qualities, and overcome our sinful/selfish desires. There are two main divisions of spiritual disciplines—those of abstinence and those of engagement. A simple way of thinking of them is that abstaining from things helps us to overcome bad desires and actions, while engaging in certain disciplines can help us develop good desires and actions.