Ben Crenshaw (1980) stated:
"Most amateurs don't know how hard to hit a putt. They are too line-conscious and don't pay enough attention to the speed of a putt. Most three-putt greens are the result of hitting the first putt very long or very short, rather than far to the left or right of the hole."
Woods (2002) stated:
"One of the keys to effective lag putting is a good read with proper speed. That's particularly true on a big breaker. What good does it do me to get the ball rolling on the correct line if I knock it six feet past the hole?"
Sorenstam (2004) stated:
“If your speed is right, it’s almost impossible to three-putt.”
A key factor in determining proper ball speed to travel the distance to the hole is whether it travels uphill or downhill. Some players have a problem in determining ball speed on sloped greens.
Editors of Golf Magazine (1973) stated:
"There are thousands of players who are consistently short on every uphill and consistently long on every downhill putt. And we mean every."It's convenient to imagine a change in hole position to account for the slope of the green. If you are putting uphill, imagine a hole that is farther away. If you are putting downhill, imagine a hole that is closer to you.
This imaginary hole position is termed the virtual hole, which defines the effective ball-hole distance required to putt on level ground.
Great advice this and so true as well