hi ,i am 40,and have been training for 15year plus.only really seriously last 5years,.i have always done the same routine week in week out cos it suits me,MONDAY-SHOULDERS,TUESDAYS-LEGS,WEDSNESDAY-ARMS,FRIDAY-CHEST,SATURDAY-BACK.I usually do 12 sets of chest,shoulders and back,legs.i do 9 sets for biceps and 9 for triceps.all the other routines i read seem to train so little,.i dont think im overtraining as each session only lasts 50mins-60mins.i am 190lbs fairly toned.is it important to switch your routine up ?