When it comes to camera straps, length does matter.
Here's how to determine the ideal strap length for yourself: Take a long piece of packing string (or any other non-stretchable string) and tie one end securely to the metal ring of your current strap.
The other end loop through the second ring and keep holding on to it tightly.
Put the camera around your neck, across your chest or any other way you'd like to carry it. Because you have the loose end of the string in your hand it's very easy to adjust and experiment with different lengths. Just make sure not to let go of the string.
Keep doing it until you find that perfect fit.
Once you have it give it a little test run. Tie the loose end of the string to the ring – make sure you are not accidentaly altering the length in the process – and walk around the house.
Don't forget to spice things up: Put on a jacket or if you like, even a winter coat.
When you are happy with the result measure the final length of the string (excluding the rings of course) and voilà, you have the ideal length for your new strap.