frequency of restringing depends on the player and the racquet, but there are a few recommended intervals. One is to restring the racquet as many times in a year as the player uses it in a week; e.g., if the racquet is used three times per week, it should be restrung three times per year. Another guideline is to restring after every 40 hours of play; if the racquet is used three times per week and three hours per session, it should be restrung approximately every five weeks. If the player has access to a tennis string tension meter (or access to a pro shop equipped with one), he may restring his racquet after he measures a loss of 25% or more of stringbed stiffness. However, many players who hit the ball hard enough to break the strings simply restring rackets whenever the strings break. United States Racquet Stringers Association The United States Racquet Stringers Association (USRSA) offers two levels of certification for stringers: the Certified Stringer and the Master Racquet Technician, of which around 350 exist worldwide. The Master Racquet Technician certification process includes testing of the stringer's ability to string a racquet, perform grip work, identify mistakes in an improperly strung racquet, and pass a written test that covers not only strings, but racquet technology as well. Since 2004, RSi, the USRSA's monthly magazine, has named a Stringer of the Year. Past winners were: Randy Stephenson, Texas (2004) Bob Patterson, Alabama (2005) Grant Napier, Tennessee (2006) Tim Strawn, Virginia (2007) Nate Ferguson, Florida (2008) Ron Rochi, Illinois (2009) Tom Parry, Minnesota (2010) Todd Mobley, Georgia (2011) John Gugel, Florida (2012) Chuck Hakansson, Georgia (2013) David Yamane, North Carolina (2014) Julian Li, California (2015) Philip van Asselt, Pennsylvania (2016) References Tennis equipment