Various general exercise related discussions. Find out what it takes to reach your fitness goals through daily effective exercise. With so many options we try to find out what works best.
Instinct is a good way. The one true way to tell is most probably by if you are making progress or not. If you have stopped any discernable gains, then it may well be time.
That said, be careful with 'adding more' when gains/loses stop. Adding more is a sure way to burn out in many cases, as at some point it becomes overwhelming and more like a bad job than what it should be.
-------------- "If it ain't broke, you aren't trying."