Yes, it is necessary but not in the way others might be saying or rejecting. We are to present 10 percent of what we profit to the Lord. We began tithing 10 percent of what we profited (plus to other needs) thirty years ago and have never had a day without food or a roof over our head or in the most simple terms, what we needed when we needed it according to our Father in Heaven.
If your flock bears 100 new sheep this year then we are to give 10 to the service of the Lord. If we clear 1000.00 we are to give 100.00 to the service of the Lord. If we make 10 cents profit then we are to give one penny to the service of the Lord. The idea of tithing is to willingly present spiritually and physically of yourself to God in Heaven. In a money driven country, we do it with money. In a cattle driven country do it with cattle. In a sheep driven economy, do it with sheep. When we leave this world we will take nothing of it with us. Tithing is a reminder of who we serve.
That said, on the receiving end it is the duty of the leaders of our churches to insure that the tithe is used to keep the doors open, pay the bills, keep a pantry, and provide a place that we may gather to sing praises onto God. It is in the new Testament in that Jesus said, I did not come to destroy the Commandments (of God, not the self righteous men) but to fulfill the prophecies. The Bible is about Jesus from Genesis to Revelation and there is no difference in the commandments between us or the old. Give 10 percent of what you profit with gladness and don't look back. Don't worry about what the church leaders do with it, they will give an account to our God for every penny. Give happily and think if it this way; God owns it all. He is telling you to keep 90 percent and do with it wisely, but still as you please.