If I carry my own bag on any of my two days of competitive golf per week, I will spent only 60 minutes in the gym before the round. If I take a caddie on one or both those two rounds, I will do my normal 90 minute workout - I have never felt too tired afterwards to swing properly. Actually, it is the other way around - my muscles feel supple and ready to go after a proper workout. Carrying one's own bag after a workout does take a toll though - that's why only 60 minutes if that is the case.
I do the normal 90 minute workout after my weekly practice round, which is early morning, when the course is empty and one can have a solid practice round over 18 holes in under 3 and a half hours.
I do all five basic muscle groups (legs, chest, arms [biceps & triceps], lats and abs), 4 x 15 reps, 70 percent power, five days per week. I only do two cardio sessions per week, on the two remaining days, normally per super circuit.
Bulky muscles don't work for golf, so I work on toning, suppleness and moderate strength, rather than straight power.
I make time for at least 10 minutes proper stretching after a workout, especially on quads, hamstrings, calves and lats.
So, basically I go to gym every day of the week, but I cut back slightly on my two days of competitive golf.