It's important to us that our finances be stewarded well, and that our giving would be in worship and honor of the Giver of all good gifts. It is a charge to all believers to give to the mission of God faithfully, generously, and sacrificially. It is not a question of what percentage should be given (in fact all belongs to God) as much as it is what percentage kept is actually needed.
God is faithful to provide our needs, and he is graciously generous to bless us. Our response is to return those blessings to him in praise. Therefore, you don't "have" to give, but it should be your joy to give to the Lord. He loves when we give with joy because it demonstrates our faith in him.
If you give to TCC your money will go towards continued intentional efforts to see the Kingdom of God grow. It goes to a church, but it is for the Church all to the glory of God.