Wheels65:
Rody - Yes, I believe that the greens do change, slightly, at irregular intervals (but I have not seen them change in the middle a day). Apex is right about a 'warm-up round' on one of the 3 hole practice games. It will give you a pretty good idea of what to expect.
I agree, Wheels, on both points
The nominal green speeds change over time in WGT-land, mostly gradually over a period of days or weeks, but occasionally abruptly. I think of it as playing right after the greens have been mowed tight for a tourney.
My first shots of the day are usually via a random CTTH to 'get in synch' with the day's meter speed, followed by a 3-hole round to get a feel for the day's green speed.
For putting I'm a formula man; I calculate required distance for putt, then add a 'safety factor' (SF) to ensure the putt at least makes it a bit past the cup. Generally my SF is + 1.5 ft, but I adjust to fit the day's tendency. As of yesterday I've increased the the SF to 2 ft or more because of current 'slower than normal' speeds.
I am a 3 rounds a week real life golfer at my CC and find the same sort of day to day and week to week variations; WGT just trying to mimic real life, my friends.