Tallied up my 55s.
Vanguard - 64 days, 17 hours, 37 minutes
Gunslinger - 60 days, 1 hour, 55 minutes
Guardian - 54 days, 9 hours, 33 minutes
Sage - 16 days, 10 hours, 47 minutes
Sentinel - 8 days, 3 hours, 3 minutes
Scoundrel - 6 days, 8 hours, 8 minutes
Mercenary - 11 days, 5 hours, 24 minutes
Sniper - 8 days, 2 hours, 38 minutes
Total - 229 days, 11 hours, 5 minutes