I guess I see two ways of looking at the Law (with variations on those themes).
1) Everything is legal, unless the Bible tells us it is not
2) Everything is prohibited, unless the Bible tells us it is not.
There are those who will show you in the Bible what you are supposed to be doing, and there are those who will attempt to put you under a law that does not even exist. If you believe that God wrote the Law,. and think you need to add to it, because God forgot a few things, that puts you in a dangerous position of trying to be more righteous than God - and I'm sure not going to try that!
I grew up in a church that pretty much took the second way of looking at things. Drinking was sin, as was smoking, dancing, playing with a regular deck of cards, etc. The strictness varied with the pastor. I remember one that prohibited his wife from buying their children clothes from the store if they could be made at home, and also prohibited her from using an electric sewing machine. Another kept his daughter away from youth group on an evening that I led devotions (as a female, I wasn't supposed to do that). I think it was that same pastor that eventually agreed to perform a marriage for a divorced woman (it was a "Biblical" divorce), but not in the sanctuary - it had to be done in his office (I never quite understood why, if the marriage was permissible, it couldn't be fully permissible. If it was not "good enough" to be done in the sanctuary, should he have done it at all?) These days, it's homeschooling, Christian schooling, quiver-full, even delaying marriage.
Take alcohol specifically. My mom and dad are teetotallers - as are other members of my family. I am not - I have a bottle of beer once in a while - more often, I'll have a glass of red wine. That is not a lifestyle of drunkeness. If you can show me in the Bible where having a drink is a sin, we'll talk again. But I will not put myself under bondage to a Law that does not exist. My dad and I disagree. But he does not condemn me for my occasional drink, and I respect him and don't drink around him - or even mention it.
Or, more recently - the "quiver full" debate. There is a difference between a quiverfull lifestyle (which I cannot do, but wish I could), a quiverfull mentality (which I probably have) and a quiverfull theology (which I cannot find). Yes, children are a gift from God and I'd love to have more - the Bible never says that we should not steward our resource and our health - in order that we can spit as many of those babies out as we possibly can.
God is pretty eloquent and I think that if He wanted to prohibit contraception, He could have spelled it out. He gave the Jews 613 laws - do we really think that He just "forgot" birth control?
I know - some will say that it was just a "given" that contraception was wrong. Excuse me, but the Jews needed something in the Law that laid out the penalty for having sex with animals!!! If they couldn't figure that one out, I'm guessing a prohibition against birth control would have had to be spelled out pretty clearly.
And then there's Onan...which many scholars today recognize as something a little deeper than birth control.
The fact is - these two things (and many others), alcohol and contraception is not in the Law. Any law against it is arrived at by methods other than God's Word. And that puts in the category of all the laws of all the teachers of the Law that put further yokes on the people. By the time Christ arrived, they "tied up heavy loads and put them on men's shoulders" and they traveled over land and sea to win a single convert, only to make him twice as much a son of hell as they were.
What God has spelled out for us, we should obey. What God has put on our hearts, we must follow. But we are under no obligation to follow another person's heart, if it is following a Law that does not exist.