Readers of The Shop know that the USGA has recently made some sweeping changes to the rules governing grooves in clubs with a loft of 25° or more. In a nutshell, the governing body of the game in the United States, Canada and Mexico has decided that the grooves on these clubs must be made smaller in volume and have edges that are less sharp. (If you are interested in reading the USGA's announcement regarding the rule changes, click here.)However, the rules kick in for different players at different times. Here are the keys dates:JANUARY 1, 2010 All products submitted to the USGA for approval must contain the new, conforming grooves.PGA Tour players, and golfers who try to qualify for PGA Tour events, will need to use equipment that has the new grooves starting on this date. Golfers who compete in the U.S. Open, U.S. Women's Open and U.S. Senior Open will need to use clubs with the new grooves as well. However, the USGA has ruled that golfers may use the older, non-conforming grooves at local qualifying tournaments for these events. At the sectional qualifying level, the new conforming grooves must be used.JANUARY 1, 2011This is a key date for weekend players because manufacturers will have to stop making and shipping clubs that contain the larger, sharper grooves. This is why we've been reporting on so many new wedges recently; companies are scrambling to get high-spin clubs into the marketplace while they still can. Still, it's important to note that retailers will be able to sell any clubs they have in stock, even those with nonconforming grooves.Amateur players who value spin may want to stock up before this date. Once supplies are gone, that's it.JANUARY 1, 2014 All USGA and R&A championships will require competitors to use the newer, conforming grooves.JANUARY 1, 2020 The USGA has said that it will evaluate the effects of the groove rules no sooner than this date.JANUARY 1, 2024 As things stand now, this is the date when the vast majority of the world's golfers will have to start using the new grooves. Before this date, golfers will be free to play with the older, larger grooves, even in rounds used for handicap purposes.