When we pray, read our Bibles, worship, and do all the other habits which make us more Christ-like, we might think of ourselves as runners training for the Olympics, doing everything we can to make ourselves medal worthy. We think that if we don't try our hardest, we might miss out on getting the highest medal, but no one else will suffer the consequences.
But the Bible informs us that we're playing on a team sport, and when we don't give it our all, the rest of the team suffers the consequences. Scripture says that all of God's saved are one body, and you are one part of that body. All the other parts need you to be the best part you can be just as much as you need your lungs, your heart, your kidney, and your liver operating at their best.
Some of us are gifted with the more traditional roles: apostles, prophets, evangelists, and teachers. Some of us have been given one of the assistive roles: wisdom, encouragement, or giving. Some of us have been given an extra large portion of one of the heart roles: mercy, faith, wisdom, discernment. There are more gifts than what I've listed here, but they all have one thing in common: you need to be doing your spiritual "exercise" to be able to put them to good use.
These gifts first and foremost are for the edification of the church. There are people at your church who need you at your best, because God put you into that congregation and gave you your gift to serve and bless those people. But it's also the people in your home, the people in your office, the people in your school, and the people in your neighborhood who need you exercising your mercy, wisdom, teaching, giving, or whatever else you've been given. Though they may not even know it, so many people are counting on you to be the person God has placed you there to be.
In my notes, several years ago, I wrote down the phrase "private devotions have public consequences". (If I heard that from someone else, I apologize for not being able to credit you.) If you think keeping your mind or body healthy is important, how much more important is it to keep Christ's body in peak condition for the work He's called us to do.