John 16:13 refers to the disciples. It should be obvious that he hasn't made believers know what's to come.

The general will of God is revealed in the Bible. The specific will of God for you in a given situation isn't something that God reveals through his Holy Spirit very often. Sometimes you can feel the Holy Spirit lead you in one direction or another.

I especially pray for a leading of the Holy Spirit when I need to make a decision and the decision must be made very soon. At times I've felt peace regarding doing it. Other times I've been disturbed in the Spirit so I had to change my decision. Once I prayed about whether or not to buy a certain used car. The mechanic said he didn't feel good about the car so we didn't buy it.