Do you know your shutter speeds well enough? To help with this question, consider the following with three lenses (24mm, 50mm 100mm full frame equivalents on your camera)
What shutter speed:
- can you comfortably and reliably hand hold
- can you comfortably and reliably hand hold after exercise
- can you hold with extra support (i.e. a mono pod or leaning against a vehicle or tree)
- freezes a person walking
- freezes someone running
- freezes a car at 50 km / per hour
- stops water falling
- blurs water in a waterfall
- is good for blurring photographs
- freezes grass blowing in a gentle breeze
- do you need to lock the mirror up when the camera is on a tripod
The answers for these images varies between focal lengths of your lens in some instances and not for others.
The key one is hand hold-ability... You need to clearly know when to be increasing the ISO or changing the aperture so that you are getting sharp photographs.
Can you check your shutter speed in the viewfinder. Do you remember to check it each time you take a photograph?
Working out your hand hold shutter speed is dependent on the lens, your technique and the megapixel count of your camera. The best way to determine this is to test different shutter speeds and physically check the resulting images at 50%. Once you work out what shutter speed you can hand hold for each of your main lenses write it down in your notebook and keep this information with in your camera bag.