I use a lens hood for every shot (with view camera lenses, I leave lens hoods attached so that I can put lenses down quickly on the front rim of the hood and know that I won't damage them). 99% of the time the hood probably makes no optical difference but gives good physical protection.

Original manufacturers' lens hoods are often very expensive - on the other hand, this supplier


has metal hoods in useful sizes (like the 77 mm you need) for about 2.50 plus very reasonable shipping. I have bought quite a few. When I bought my RB outfit, I included a Mamiya compendium hood, which is a thing of wonder but which I have never used (too bulky, can't stand the lens on it).