From the White Sands Soaring Association Handbook:
If you do not have a pilot certificate, you will follow the outline below:
1) Obtain a student certificate. Your instructor will help with this
2) Fly with your instructor until both you and the instructor are satisfied that you can safely “solo” the aircraft. Expect a minimum of 25 flights at the rate of 3-4 per session. At this point the instructor will administer a short written test on the particular glider you are flying and endorse your logbook for solo flight.
3) Take the FAA written exam for your private pilot certificate. Your instructor will help you with the preparation.
4) Practice solo flight.
5) Take the practical test, or “check ride”. The practical test consists of an oral exam and flights with a FAA examiner. It is somewhat analogous to a driving test. Your instructor will assist you in preparing for this and be present during the test.
6) After you pass the practical test and have been issued a private pilot certificate, you can legally carry passengers.
Steps 1 and 2 above can be combined, as can steps 3 and 4.
If you have a power pilot certificate but not a glider rating, expect the following:
1) 10-15 instructional flights, depending on the individual.
2) The FAA written test is not necessary.
3) Written test on particular glider being flown. Solo practice.
4) Preparation for check ride.
5) Check ride.
If you have a glider rating, expect the following:
1) 3 to 6 instructional flights, depending on the individual.
2) Written test on particular glider being flown
Note that it is WSSA policy to administer a separate written test for each different glider being flown with an attendant briefing by a Club CFIG.
If you have a glider rating and your own glider, expect a briefing on Club and local airfield procedures before flying