The main requirement of the PGA Champions Tour (formerly known the Senior Tour) is that all golfers be at least 50 years old. Beyond that, golfers qualify for the Champions Tour by their money list ranking, winning previous events, receiving a sponsor's exemption, winning a Monday qualifier or by finishing within the top five of the previous year's Champions Tour Qualifying Tournament.
All Champions Tour events have a field of 78, the first 60 places are filled with up to 30 players who are in the top 70 of the all-time combined PGA Tour and Champions Tour money list or with up to 30 players who finished in the top 50 of the previous year's Champions Tour money list and are not otherwise exempt.
The remaining 18 spots are filled with members of the World Golf Hall of Fame, winners of Champions Tour events in the previous 12 months, five players from the previous year's qualifying tournament, previously exempt players coming off medical exemptions, the top four players in their first two years of age eligibility with multiple PGA Tour wins, and one spot for the highest finisher, not already exempt, within the top 10 of the previous week's tournament . A top 10 finish does not qualify a player for a major, and a top 10 finish in a major does not qualify a player for a regular tournament.
There are also up to five spots available for sponsor's exemptions and up to four spots available for Monday qualifiers, but these nine spots are subject to reduction or elimination depending how well the other 69 spots fill out. Invitationals and majors have their own entry criteria.