Isn't that the truth... I fly fish, often solo, and how many times have I taken some "iffy" chances just to get to a promising pool...
if you have your belt on with your chest waders, how much does this improve your chances of getting to shore?
A lot.
In fact, I wouldn't be here typing this if it hadn't been for my wading belt snugly fitted around the waist.
I took the mother of all dunks in the upper vedder a few years ago in late January - literally went under. The thermal shock wouldn't let me breathe for a good 10 seconds or so. Fortunately, the waders did NOT fill with water and the air trapped under the belt in the waders actually kept me afloat. After a good 60-70 yards of floating downstream (legs first), I got to some slower water and slowly crawled back to shore. Scary experience!
Please wear a wading belt with your waders at all times , and invest in a PFD. It makes the difference between life and death more often than not.