Some interesting layouts for this object on the goggles....

Heres what I did. Just two cylindrical maps (inside and out) for the main bit. Planar x2 for the circles...and the nose pieces was a quick auto map into three bits.

JSprogg is right about keeping the seam count down as much as possible. Sometimes its unavoidable on certain objects so dont always feel you need to do stuff all in one go. As dave says you can get stretching and adding the extra piece can help. Above all just make sure the uv is clean and the uv texturemap numbers are square. When testing for stretching I increase the u and v repeats on the test pattern this way you can spot stretching easier as opposed to bigger squares where it isnt as obvious between each poly

cheers
J