A golf lifetime is spent trying to attune your brain and your hands to the pace and speed of the many and various putts you encounter. There’s no other choice but to take them case by case, but Craig Farnsworth, a Colorado-based eye doctor-turned-sports-vision-specialist who has written two books on putting, would have you bear in mind four basic rules of speed and pace on the putting green.
1) Most putts have three separate speed zones: the initial burst, the basic rolling speed, and the braking speed. You have to try and visualize all three to hit any kind of lengthy putt with the right force. Two greens of fairly comparable speed in the initial-burst and cruising-speed segments of a putt can differ in how they make your ball behave as it slows down. Some have extra “roll out” that keeps them in motion for a surprising extra distance.
2) Putts break the least when they’re going their fastest and break the most when traveling their slowest. (Exception would be if there is a huge mound or ridge at the beginning of a putt, and level ground near the hole)
3) On fast greens, your putt travels slowly for most of its length, losing energy gradually; on slow greens, your putt travels quickly for most of its length, losing energy and speed in a short segment at the end
4) Most side-breaking putts (especially on slick greens) have an “interstate highway” effect. For example, on right-to-left breaker, you could get it going quickly toward the hole in the “left lane,” more slowly in the middle lane and slowest down the right lane. The more speed, the less break the putt will take and the less break you should play.