You go to church nearly every Sunday. Perhaps you attend midweek services, pay your tithes, and give offerings. Why would you need to volunteer?
One of the reasons for church volunteerism is that it causes you to grow closer to others who are grounded in your church and helps you connect to the church body. When you join as an usher and greet people for service and help them learn more about the church, become an assistant and help teach the younger children, or spend part of your Friday cleaning the foyer, you begin to learn more about the people you're working alongside. After all, we are to know those who labor among us. You also begin to care more about the things you're involved with and understand that the church is not perfect, but is definitely worth the effort.
As you begin to volunteer, you stop only taking in the preaching, teaching, counseling, and wisdom being poured out, and start giving back. Instead of just being a pew-warmer watching the show, you have the ability to start a true relationship with the church - and relationships go both ways. It's an opportunity to go from wondering when the preacher is going to notice or offend you to actually being a part of the lifeblood of the church. In a way, volunteering can keep you from feeling isolated and giving you the urge to church-hop, trying to find a church that will make you feel like you're a part, important, and loved just like you felt as a new member a year ago. Believe it or not, this typically can be remedied by action on your part - deciding to grow with the church as a volunteer and helping it move forward instead of staying the same and feeling left behind.
As you take the initiative to begin a real, two-way relationship with the church and know those who are laboring with you by volunteering, you gain experience, knowledge, and understanding. You learn how to work with others in the church and how the church operates behind the scenes. You see the gaps where help is necessary and can alleviate the burden many faithful volunteers have been carrying as they held on until someone like you came along to help. If you complete your volunteering with excellence, God will cause you to be blessed and give you a greater measure of authority. This is especially important for those who feel called to ministry.
Knowing those that labor among you, having a solid, grounded, two-way relationship with the church, and growing in authority are just three of the reasons you should volunteer in your church. If you haven't already, take the first step and contact your leaders to see what it is that you can do in your church.