Congrats on the new tool! And yes, get the shoulder strap. Very useful addition. My dealer tossed one in for free when I bought my Echo. (It's a Stihl strap, which he said was more comfortable.)
When I'm weedwhacking the hillside in our back yard, it's not always possible to keep the debris from flying at me. I finally got smart and started wearing my chainsaw chaps just to keep from coating my jeans with weed and grass splatterings. I also wear my chainsaw hardhat/face shield. Took a few rocks to the face before I figured that one out.